APCSP Midterm Review Questions

Which of the following BEST provides what the purpose of a heuristic in programming? a) To provide an answer to a problem that can be solved in a reasonable time and an approximate solution is acceptable. b) To provide an answer to a problem that can be solved in a reasonable time and an exact solution is needed. c) To provide an answer to a problem that cannot be solved in a reasonable time and an approximate solution is acceptable. d) To provide an answer to a problem that cannot be solved in a reasonable time and an exact solution is needed.

Choice 'C' is the correct answer. The definition of a heuristic is a technique that allows the user to find an approximate answer in a reasonable amount of time. We use heuristic algorithms when problems cannot be solved in a reasonable time and they do not have an exact answer.

Which of the following statements about IPv4 addresses are NOT true? a) There are no rules or guidelines for creating a new IP address. b) Each IP address has a network prefix and may have various subnet and interface IDs. c) Each of the octets in an address can be any number between 0 and 255. d) IP addresses might have prefixes to identify what routers or subnets to which the address belongs.

Choice A is the correct answer. These ARE standards and guidelines for each newly created IP address. For example, certain numbers are reserved for specific kinds of addresses. These other choices are all true. An IP address is hierarchical; each part refers to a different prefix as in choice B. The octets can be any number between 0 and 255 as in choice C and the prefixes of the address refer to routers or subnets related to the address as in choice D.

Which of the following statements is true regarding the networks that make up the Internet? Select TWO answers. a) If one network crashes, all other networks are affected. b) The World Wide Web is one of the networks that is connected to the Internet. c) Different types of networks can be connected in order to transfer data and communicate d) All devices that are connected on a network uses the same protocol

Choice C is true; routers can be used to connect different types of networks to create an internetwork. The routers act as translators between the networks and allow for communication between devices. Choice D is also correct; any device connected to a network (such as an Ethernet or Wi-Fi network) must use the protocol specified by the network so that all devices behave the same way. Choice A is false; the Internet is extremely redundant, meaning that if one network is down, the data will have many other paths to travel. Choice B is also false; the World Wide Web is an information system that runs on the Internet; it's not a network.

You have signed a contract with your internet service provider (ISP) that guarantees you a constant download capacity of 10 gigabytes (GB) per hour. You are downloading a video from your favorite movie website, and the video has a file size of 20 GB. The average amount of time it takes a packet of information to travel from the movie website to your computer is 2 milliseconds (ms). It takes just over two hours to download the entire movie. Considering this information, which of the following statements is true? a) The latency is 2 ms and the bandwidth is 20 GB. b) The bandwidth is 2ms and the throughput is 1movie/2hrs. c) The latency is 10 GB/hr and the bandwidth is 20 GB/hr. d) The latency is 2ms and the bandwidth is 10 GB/hr.

Choice D is the correct answer. Latency is basically the delay or the amount of time it takes for a packet of information to travel from a source computer to a destination computer. It is commonly reported in milliseconds (ms). In this example, the average amount of time it takes a packet of information to travel from the movie website to your computer is 2 milliseconds (ms), so 2 ms is the latency. Bandwidth is the size of the pipe or the capacity. A common misconception is that bandwidth is the speed, but it is not. It is normally reported in the number of bytes (or bits) per unit of time. In this example, the download capacity is 10 gigabytes (GB) per hour, so the bandwidth is 10 GB/hr. Choice A is an incorrect answer. The latency is reported correctly at 2ms, since latency is the delay that it takes a packet to travel from the source computer to its destination. However, bandwidth is reported as the number of bytes or bits per unit of time. In this choice, the unit of time is not indicated and therefore there is no basis to understand 20 GB means. Choice B is an incorrect answer. Throughput refers to the number of units that can be downloaded in a given time period. In this example, we are dealing with the movies and it takes about two hours to download the movie. Therefore, the throughput can be stated as 1 movie/2hrs. However, this choice is incorrect, since the bandwidth is 10GB/hr. Choice C is an incorrect answer. Latency is basically the delay or the amount of time it takes for a packet of information to travel from a source computer to a destination computer. In this example, the latency is 2 ms.

Which of the following domain names are part of the same top tier? Select TWO answers. a) www.collegeA.edu b) www.collegeA.net c) www.collegeB.edu d) www.collegeB.com

Domain names are structured in a hierarchical manner. The top tier of a domain name is found all the way to the right of the name. Thus, choices A and C both come from the same top tier (.edu).

Which of the following explains why open standards make encryption more secure? a) They allow everyone to develop their own standards and practices for encryption. b) They are developed and reviewed by committees of experts and adopted by all Internet users. c) They make it easy for people to create and implement new encryption methods. d) They do not make encryption more secure; open standards make it easier for third parties to intercept and decode messages.

The fact that open standards are developed by panels of experts make them very trustworthy. Also, since the encryption is created with open standards, we can be sure that all Internet users are obeying the same rules when encrypting private information. This makes choice B correct. Choices A and C are both incorrect for a similar reason. The open standards are adopted across the Internet. This means that users cannot make their own practices to use on the Internet. Choice D is also incorrect; the amount of time and thought put into the open standards ensures that encryption on the Internet is secure.

Organizing Monica wants to sell her stuffed animal collection online. Her plan is to organize them alphabetically, then use the Internet to look up the value of each stuffed animal one by one. She'll put the data in a spreadsheet which will be organized alphabetically. Which of the following are part of Monica's algorithm? a) Only sequencing b) Only iteration c) Sequencing and selection d) Sequencing and iteration

The first part of Monica's algorithm requires sorting or sequencing the stuffed animals. She must then go through them one by one, which is iteration. This makes Choice 'D' correct.

Which of the following number systems uses the symbols A through F? a) Binary b) Octal c) Decimal d) Hexadecimal

d

Alex has written code implementing a prey-predator relationship. He has coded a class from the sharks (predator), the fish (prey), and a graphical view to show these creatures on a grid moving about in an ocean of blue. Though the code appears to work correctly, Alex finds that the implementation is terribly slow. If he has more than 25 or so creatures in his ocean, the computer slows to a crawl and it takes hours to run his simulation. He would like to have the simulation running with thousands of creatures in the ocean. What should you recommend to Alex to improve the implementation of his simulation? Select TWO answers. a) Consider implementing his code in a different language - some languages are better suited to running simulations with a large number of objects than others. b) Consider choosing a different problem - the ocean is too big a place to create a simulation on a modern computer. c) Consider his graphical implementation - perhaps there is a way to speed up the graphs he has paired with simulation. d) Consider adding a plankton class for the fish to consume - perhaps adding a layer of complexity will give insight into the fish-shark relationship.

Choice 'A' and Choice 'C' are the correct answers. Some languages are ill-suited to certain problems. It is possible that Alex is implementing his algorithm in a graphical language that is designed to handle showing only a small number of objects on the screen. He could consider a different programming language, or simplifying the graphical implementation

A salesperson is given a list of cities and the distances between them. The salesperson has to visit each city exactly once and then return to the first city. What is the shortest possible route the salesperson could take? Assume an actual salesperson is trying to determine the shortest route she can take to visit 18 cities. She could use a computer program to calculate the distance of every possible route and then select the shortest one. Alternatively, she could use a heuristic to find a route. Which of the following reasons would justify the use of a heuristic? a) She has to pay for her own gas. b) She has to leave in an hour. c) She could potentially get a raise for being more efficient on her sales route than her coworkers. d) She doesn't want to put too many miles on her car.

Choice 'B' is correct. A heuristic is a shortcut that leads to an approximate solution, and in this scenario, the salesperson can accept an approximate solution. Her only concern is leaving quickly, so a shortcut to find the route would be ideal.

Monica realizes there is probably a big market for a program that could help users organize a stuffed animal collection. She envisions a program that will essentially be a list of lists. Each stuffed animal will have a list of information (year made, value, condition, etc.) and those lists will be stored in a master list called masterList. Monica writes the following algorithm for the "pickToSell" procedure: The procedure will sort masterList according to the value of the stuffed animals (most valuable to least valuable). Then the procedure will ask the user for a desired value. The procedure will print out the names of the stuffed animals that have a value greater than the desired value. Rachel and Chandler will each create a version of this program. Rachel plans to use Python to implement the program and Chandler is going to use Java. Which of the following statements are true? Select TWO answers. a) Monica's algorithm will be more helpful for Chandler than Rachel b) Rachel and Chandler will have to use iteration, selection, and sequencing to execute this algorithm. c) It's important that Monica's algorithm is clear and readable. d) The algorithm that Monica wrote can be implemented on a computer as is.

Choice 'B' is correct. The algorithm that Monica described involves putting a list in order (sequencing), going through each item in that list (iteration) and picking items that match a certain criteria (selection). Choice 'C' is also correct. Since Monica is telling Chandler and Rachel what she wants the program to do, she will need to be very clear and make sure her algorithm is readable.

12. In data compression, there are many different methods for compressing data. We have many different protocols because there is no one method that provides the absolute best compression for all files in a reasonable amount of time. Which of the following is the BEST term for the above example? a) An algorithm b) A heuristic c) A selection d) An iteration

Choice 'B' is the correct answer. The definition of a heuristic is a technique that allows the user to find an approximate answer in a reasonable amount of time. We use heuristic algorithms when problems cannot be solved in a reasonable time and they do not have an exact answer

The Manhattan distance is often used when talking about how many city blocks two locations are from one another. If you are in a city with only north/south streets and east/west streets and trying to get to a location that is less than 10 miles east and 2 miles north, then which of the following paths will NOT get you to the destination? a) Going north 2 miles, then east 10 miles. b) Going north 3 miles, then east 10 miles, then south 1 mile. c) Going 1 mile north, then 1 mile east twice, then 9 miles east. d) Going 1 mile east 3 times, then 1 mile north 3 times, then 7 miles east, then 1 mile south.

Choice 'C' is correct.

Which of the following is NOT an example of a heuristic? a) Meredith estimates that each floor tile is 10 inches by 10 inches. She counts floor tiles to determine the size of a room. b) Avaya begins reading a positive, well written review for a product online. Based on the quality of the writing, she assumes that the product must be good without reading the rest of the review. c) Martha is instructed to inventory all of the items in three aisles of a grocery store. She counts everything item by item and writes down the totals. d) Sarah, a college junior, goes to the campus center to give a tour to a high school student. She sees a crowd of people and assumes that the person wearing the high school letter jacket is the prospective student.

Choice 'C' is correct. In this scenario, Martha must count every item in three aisles of a grocery store. There is no shortcut and she gets an exact answer, not an approximate one. A heuristic can be described as a shortcut that leads to an approximate answer, so this choice is not a heuristic.

Pierre de Fermat was a French lawyer who practiced mathematics as an amateur. He was famous for challenging some of the greatest mathematical minds of his time to solve problems that he created. Generally considered one of the key pioneers in analytical geometry, probability, and optics. However, he may be most famous for a note he left in the margin of a book where he claimed that a^n+ b^n does not equal c^n For any power over 2. Fermat's Last Theorem confounded mathematicians for centuries because they could not provide it to be correct or incorrect. In the year 1994; approximately 300 years after he posed the statement a mathematician from Princeton was about to prove that it was correct for all values n > 2. A textbook from 1980 might describe the problem as which of the following? a) Decidable, because a solution was certain but had not been written down yet. b) Decidable, 200 years had offered time for some numbers to be tested correct. c) Undecidable, no algorithm had been determined to work for all inputs. d) Undecidable, computers were too simple to test many cases at the time

Choice 'C' is correct." The full solution was discovered in 1994, so in the year 1980 the problem would have been thought of as incomplete. Without an algorithm to solve the problem, the theorem would have been considered undecidable.

A programmer wrote the following segment of code to find the lowest test score in a list of test scores. Note that there is at least one test score. Line 15. min 999 Line 2: FOR EACH score IN testScores Line 3: { Line 4: IF (score < min) Line 5: { Line 6: min & score Line 7: } Line 8: } Line 9: DISPLAY (min) Now the programmer has been asked to write some code to find the maximum test score from a list of test scores, so she uses the previous code as a starting point. The first thing that the programmer does is change the variable name from min to max everywhere it is referenced in the code. What else needs to be changed in order to find the maximum test score from the list? 1. Replace Line 1 with the following: max < -1. II. Replace Line 4 with the following: IF (score > max) III. Replace Line 6 with the following: score & max a) I only b). II only c) Both I and II d) Both II and III

Choice 'C' is the correct answer

Consider the following algorithms. Assume that you have a deck of cards with numbers on them, and you are looking for a card with a particular number: Algorithm 1: 1. look at the middle card in your deck. 2. if correct, done! You have found what you are searching for! 3. if you are looking for a larger number, discard the lower half of the deck 4. else, discard the upper half of the deck 5. return to step 1 Algorithm 2: 1. look at the first card in your deck. 2. if this is what you are looking for, great! You have found what you are searching for! 3. discard the first card in your deck 4. return to step 1 Which of the following statements is TRUE? a) Both algorithms will find the value you are looking for in any list. b) Neither algorithm will find the value that you are looking for in any list. c) Algorithm 1 requires the list be already sorted. Algorithm 2 will always work. d) Algorithm 2 requires the list be already sorted. Algorithm 1 will always work.

Choice 'C' is the correct answer.

Assume you have note cards with 20 student names on them. You want to sort them, and your friends suggest two different methods of sorting the cards. Alice suggests the following: - Put all the cards on the table - Find the one which is first in alphabetical order, and place it in a pile Find the next one in alphabetical order, and place it in the pile. Repeat until done. Elizabeth suggests: - Put one card on the table. - Look at the next card. - Place it in front of or behind the first card based on alphabetical order. - Look at the card. - Place it alphabetically in the correct location relative to the cards currently on the table. - Repeat until done. Which of the following best describes the situation outlined above? a) Alice has a more efficient algorithm for sorting the names. b) Elizabeth's algorithm is the most efficient sorting algorithm ever designed. c) Either Elizabeth's or Alice's algorithm could be used to sort the names. d) This is an example of combining the algorithms suggested to create a better solution to the problem.

Choice 'C' is the correct answer. Multiple algorithms can be used to solve the same problem.

Emergency rooms use a triage procedure to emit patients based on need. The process involves a nurse asking several direct questions to determine which people need to be helped quickly. What term in computer science best describes this process? a) Diagnosis b) Documentation c) Machine learning d) Heuristic

Choice 'D' is correct. The triage process allows the hospital to quickly collect information about a situation and make a judgement about what is most likely needed. Formal medical diagnosis is much slower and can often be an unsolvable problem. The triage process is not 100% accurate, but provides a 'shortcut that allows them to react quickly. This is the same mechanism as a heuristic.

The Entscheidungs problem was a problem posed by David Hibert. The Entscheidungs problem looks for an algorithm that will determine if any mathematical statement is provable from known axioms. The problem looks for a simple "yes" or "no" answer, however, just eight years after the problem was posed it was proved that there is no one algorithm that can be constructed that always lead to a correct "yes" or "no" answer. What do we call these types of problems? a) Unpredictable b) Unsolvable c) Unreasonable d) Undecidable

Choice 'D' is the correct answer. The definition of an undecidable problem is that we can write an algorithm that will run in some instances, but will not always lead to a correct "yes" or "no" answer

The term protocol is used quite a bit when referring to computer networks. Of the following, what is the best definition of protocol? a) A protocol refers to the defined rules that allow two connection points to talk to each other b) A protocol is the original model of a new device on the network c) A protocol is the design of a network, generally created by IT administrators. d) A protocol is the "initial call" of a procedure to facilitate the transfer of data over the internet.

Choice A is the correct answer. When referring to computer networks there are many protocols that are used to allow communications. For example, HTTP stands for Hypertext Transfer Protocol and is used for transmitting web pages and other data/resources across the internet. A protocol is simply the established collection of rules that facilitate this communication. A protocol can be defined for the hardware layer, the application layer, or for other layers. Choice B is an incorrect answer. The original model of something, like a new device on the network, is a prototype, not a protocol. Choice C is an incorrect answer. A network design is the planning and design of a network, generally created by IT administrators. Choice D is an incorrect answer. This choice was a distractor using a play on the word bases "proto" and "col"

Which of the following statements are TRUE on the Internet? Select TWO answers. a) Most network routing on the Internet is hierarchial. b) Domain names and IP addresses are assigned randomly. c) The structure of the Internet makes it difficult to grow significantly. d) Most data can follow more than one path to the destination device.

Choice A is true; most information packets are passed around larger gateways until they come to gateways that can reach the destination directly. It's often called a "backbone" network because there are small routers connected to one line of larger routers. The hierarchial routing system decreases congestion and makes it easy to transfer data. Choice D is also true of the Internet. The Internet is redundant, meaning data can usually travel by multiple paths. Choice B is incorrect; there is a structure to both domain names and IP addresses that makes them very far from random. Choice C is also incorrect; the Internet is structured so that it's easy to scale.

The Internet Engineering Task Force makes decisions by rough consensus, not by the majority of votes. What does this ensure about the Internet? a) Although the standards that govern the Internet (like IP and DNS) might change, they will not be affected by a small group or party b) It is incredibly difficult to change the common protocols and standards of the Internet once they have been created c) The standards created by the IETF have to be narrow and specific because so many people all need to agree on the decisions being made d) It is hard to persuade people to join the IETF since decisions rarely affect the way the Internet is currently used.

Choice A is true; since the IETF is looking for complete or nearly complete consensus on issues, it is difficult for a private company or government group to sway the decision making. There will not be an issue that is won by a narrow amount of votes. Instead, an entire group of people representing different aspects of Internet use will all have to agree. Choice B is not true: the IETF meets several times a year in order to edit and change any existing standards. As long as the group agrees on a change, the protocol can evolve. Choice C is also false. In fact, standards are often better when they are wide and open to interpretation. This openness creates an Internet where people can experiment. Choice D is also incorrect; the changes created by the IETF always affect the way we use the Internet.

Let's assume that your Internet Service Provider (ISP) promotes that their bandwidth is 2 MB per second. The latency of a packet traveling from your favorite website's server to your computer is 1 millisecond (ms). Which of the following scenarios would MOST LIKELY have the greatest potential for increasing the speed of information flow from your favorite website's server to your computer? a) Your ISP changes its bandwidth to 2.5 MB per second, and latency from your favorite website's server to your computer is changed to 1.5 ms. b) Your ISP changes its bandwidth to 2.5 MB per second, and latency form your favorite website's server to your computer is changed to 0.75 ms. c) Your ISP changes its bandwidth to 1.5 MB per second, and latency from your favorite website's server is changed to 0.75 ms. d) Your ISP changes its bandwidth to 1.5 MB per second, and latency from your favorite website's server is changed to 1.5 ms.

Choice B is the correct answer. Bandwidth is the size of the pipe or capacity. A common misconception is that bandwidth is speed, but it is not. It is normally reported in the number of bytes (or bits) per unit of time. In this example, the ISP's capacity is 2 megabytes (MB) per second. Any increase of the bandwidth, such as going from 2 MB/sec to 2.5 MB/ssec, would increase the capacity and potentially increase speed of data transfer to your computer. Latency is basically the delay or the amount of time it takes for a packet to travel from a source computer to a destination computer. It is commonly reported in milliseconds (ms). In this example, the average amount of time it takes a packet of information to travel from your favorite website to your computer has been decreased from 1 ms to 0.75 ms. Therefore, the delay has decreased which could potentially increase speed of data transfer. Since BOTH bandwidth and latency have improved, this choice is the best answer. Choice A is an incorrect answer. The bandwidth has increased from 2 MB/sec to 2.5MB/sec, which increases capacity and potentially increases speed. However, latency has increased from 1 ms to 1.5 ms. This means that the delay in sending packets from your favorite website to your computer has increased by 50%, which potentially slows the speed of data transfer. Choice C is an incorrect answer. The bandwidth has decreased from 2MB/sec to 1.5 MB/sec, which decreases capacity and potentially decreases speed. Latency has decreased from 1ms to 0.75ms. This means that the delay in sending packets from your favorite website to your computer has decreased, which potentially increases the speed of data transfer. Choice D is an incorrect answer. The bandwidth has decreased from 2MB/sec to 1.5MB/sec, which decreases capacity and potentially decreases speed. Latency has increased from 1 ms to 1.5 ms. This means that the delay in sending packets from your favorite website to your computer has increased by 50%, which potentially slows the speed of data transfer. This is the worst option of all four choices.

HTTP is an acronym for Hypertext Transfer Protocol. Of the following, which is the best definition of HTTP? a) HTTP is a protocol used to create and implement web pages. b) HTTP is the protocol for translating a web page's address to an Internet Protocol address. c) HTTP is the protocol for communicating with web servers and transferring web pages and other data back to a browser. d) HTTP is the address most people use to access a web page.

Choice C is correct. As stated in the prompt, HTTP stands for Hypertext Transfer Protocol. It is an application protocol used to transfer files (such as web pages, spreadsheets, documents, images, video, etc.) over the internet. It is considered the basis for transmitting data over the internet. Choice A is an incorrect answer. Not to be confused with HTTP, HTML stands for Hypertext Markup Language and it is used to create web pages. Choice B is incorrect. DNS (Domain Name Service) is the protocol for translating a web page's address to an IP address. Choice D is incorrect. URL stands for Uniform Resource Locator. A URL is the more readable address that most people use to access a web page.

Which of the following statements is an accurate interpretation of bandwidth speed? a) The type of Internet service provided by a company. b) The number of files that can be downloaded in a set amount of time. c) The time it takes a piece of data to reach its destination. d) The rate at which data is downloaded in a set amount of time.

Choice D is the correct answer. Bandwidth is the rate at which data is transferred in a fixed amount of time. This is usually measured in bits per second or kilo-bits per second. Choices A and B are both incorrect. Choice C refers to latency, the amount of time it takes data to reach the end host.

The following quotes are from Wikipedia regarding different computer languages. Given the following information, which would you likely recommend to a precocious 6th grader who wants an introduction to computer programming? Select TWO answers. A.) Java: "Java is a general-purpose computer programming language that is concurrent, class-based, object-oriented, ...It is intended to let application developers 'write once, run anywhere' B.) Alice: "Alice uses a drag and drop environment to create computer animations using 3D models." C.) Scratch: "Scratch is a visual programming language...[It can be used to create games and provide a stepping stone to the more advanced world of computer programming." D.) Python: "Python is a widely used general-purpose, high-level programming language. Its design philosophy emphasizes code readability. The language provides constructs intended to enable clear programs on both a small and large scale."

Choices 'B' and 'C' are the correct answers. Different computer languages are better suited to different tasks. Visual, drag-and-drop style languages are better suited than general purpose text-based languages for younger students.

Computer viruses come in many forms. Which of the following descriptions is most Unlikely to be describing a virus? a) It is attached to a program and runs each time the program is opened? b) It is disguised as an accounting program and runs when the program is opened. c) It is sent as an email that asks recipients for their credit card numbers. d) It is a piece of software that looks for security holes in a network and uses those holes to infect other computers.

Choices A, B, and D all describe viruses that have been created by a programmer that can wreak havoc on a computer. Choice A is a typical virus that can be attached to any kind of program. These viruses can duplicate and attach themselves to other programs. Choice B describes a Trojan horse; this virus is disguised as a regular program. Choice D describes a worm, a small piece of software that finds and takes advantage of security holes. Choice C is the correct answer because it describes phishing, not a virus. Phishing is a scheme where official looking emails are sent that request personal information.

Rachel is planning on writing code that will have to do with very large numbers. Which of the following is the most important issue she should check before writing her code? a) Rachel should look up how many bits are used to store integers and floating point numbers in the programming language she is using. b) Rachel should reset her machine to store data using hexadecimal instead of binary. c) Rachel should run a program to ensure that she has enough memory on her machine just to write the program itself. d) Rachel does not have to worry about the size of the numbers.

a

Which of the following is an example of abstraction? a) Jimmy is teaching his daughter how to drive a car. Instead of explaining how the engine works, he tells her that turning the key will start the car. b) Mr. Higgins gives his student a hint by eliminating an answer choice on a multiple-choice quiz. c) Steve explains how to drive to New York using clear and concise instructions. d) Miles explains the concept of multiplication using hands-on materials like blocks.

a

"There are 10 types of people in this world: Those who understand binary, and those who don't." Why might computer scientists find this statement humorous? a) There are ten types of computer programmers in the world. b) 10 (binary) = 2 (decimal) c) 10 (decimal) = 1010 (binary) d) 10 (hexadecimal) = 16 (decimal) = 1 0000 (binary)

b

Doris needs to represent 26 different letters using binary. What is the minimum number of binary digits she will need to represent this many letters? a) 4 b) 5 c) 6 d) 26

b

Jerry and Ron are each working on programs with different purposes and implementations. They each use the following binary sequence in their programs: 0110 1100 0100 0111 Which of the following statements is true? Select one answer. a) This binary sequence MUST represent the same type of data. b) This binary sequence MIGHT represent the same type of data. c) This binary sequence CANNOT represent the same type of data. d) It is impossible for Jerry and Ron to use this binary sequence in their programs.

b

Jim wrote a procedure that calculates a base raised to a certain exponent. The procedure has two parameters: case and exponent. This procedure can be seen below: Which of the following changes could be made to the above code without altering the outcome? a) Change "x x * base" to "x * base x" b) Change "x x * base" to "x base * x" c) Change "REPEAT exponent TIMES" to "REPEAT UNTIL (exponent = 1)" d) None of these would work without altering the outcome.

b

Scientists want to model the population changes of a certain kind of snake that eats rodents and mostly lives under rocks in the colder months. The model will be created using a computer program. Which of the following statements are TRUE about the scientists' model? Select TWO answers. a) The scientists can disregard the population of rodents when creating their model b) The scientists can disregard the coloring, scales, and physical attributes of the snakes when creating their model. c) The scientists could use the model to find the likelihood that the snakes become endangered or extinct. d) The scientists should be cautious with their model so as not to disrupt the actual population growth or decay of the snakes.

b

In August 2005, Hurricane Katrina wreaked havoc on the Gulf Coast. It was the costliest and one of the deadliest hurricanes in US history. Since that time, the simulations that meteorologists run to track and model hurricanes have significantly improved. With global climate change, scientists expect the hurricane season to become longer and the number of large storms to increase. However, they expect the advances in modeling to improve our ability to predict and prepare for storms in the future. Which are contributing factors to the improvements in modeling and simulation of hurricanes? Select TWO answers. a) Changes in the climate make the prediction of storm intensity and direction easier to extrapolate from historical data. b) Changes in available computing power as well as refinement of the software improve the ability to produce timely predictions of storm changes. c) Improvements in the quality of data collected on the ground, from airplanes, and from space have improved, allowing the level of detail in the models improve significantly. d) Improvements in the levee system throughout the lower Mississippi region are likely to mitigate the economic impact of future storms.

b,c

Supercomputers are machines that, as of 2015, could compute quadrillions of floating-point operations per second. That is, their performance is multiples of 10^15 operations per second. These machines are used for a variety of things, including simulating earthquakes, nuclear reactions, and the big bang. In fact, supercomputer simulations have at this point replaced the testing of actual nuclear arms. Some of the advantages to these simulations include: Select TWO answers. a) Models can incorporate all of the complexities of nuclear reactions. b) Models are cheaper than building multiple designs and testing each in the real world. c) Modern supercomputers are cheaper than a mid-size car. d) Simulations come without the environmental risks associated with nuclear tests.

b,d

Binary number sequences can be used to represent multiple types of data, including images, data, numbers, text, and sound. The computer determines what type of data a number sequence represents by the context in which it is used. Which of the following could NOT be represented by the sequence 0100 0001? a) A b) 65 c) 1011 1110 d) Amount of red in RGB model.

c

Computerized simulations are run repeatedly on tropical storm and hurricane data. As a storm approaches land, these models predict the likelihood of landfall along the coast and the expected intensity of the storm as it makes landfall and continues inland. Which of the following is true about these models? a) Models are based on past storms and thus should not be relied upon to provide accurate predictions of what new storms are likely to do. Thus, these simulations should be used to predict landfall location but not storm intensity. b) The quantitative data collected by the satellites and other sources is converted by supercomputers into binary data. Because binary data is discrete, we expect it to be better at predicting the intensity that where the storm will make landfall. c) Regularly updating the models with data that is being collected from land, air, and space-based instruments allows the models to continually provide updated predictions of where the storm is likely to hit and at what intensity. d) As models are based on hypotheses that are based on historical data, these simulations should continue to be used to modify the parameters of the computer models, but should not be released to the public during the storms, as they may not be completely reliable.

c

Makenzie is planning to write a program to play tic-tac-toe. She also knows that she has an assignment coming up at the end of the month that will require her to draw a checkers board on the screen. She plans to write the following procedures: square(size) row(tiles, size) grid(tiles, size) In her planning, she intends to start with code to draw a square, then use square(size) in her row(tiles, size) definition, and finally to use row in her grid(tiles, size) definition. Which is the highest level of abstraction? a) square(size) b) row(tiles, size) c) grid(tiles, size) d) None of these are abstractions.

c

Meteorologists use simulation software to predict the weather for upcoming days. In this context, which of the following are reasons to use simulation software? I. Law enforcement can use the simulation software to gauge the risk of flooding and evacuate residents before it is too late to evacuate. II. NASA can determine if it is safe to proceed with the launch of a space shuttle. III. School districts can anticipate inclement weather and cancel school before students arrive. a) I and II only b) II and III only c) I and III only d) I, II, and III.

d

Why do computer scientists often prefer hexadecimal over other representations? a) Hexadecimal uses fewer digits than binary. b) Hexadecimal representations use letters as well as numbers. c) Computers, at their most basic, use hexadecimal, not decimal or binary. d) Early typesetting procedures that predate modern computing use a base-16 system to represent alphanumeric characters.

a

Computer models have largely replaced wind tunnels in testing the aerodynamics of automobiles. This has allowed rapid testing of many variations in design without having to build physical scale models of every possible design configuration. Which of the following design components should be included in one of those models? Select TWO answers. a) The ground clearance of the vehicle. b) The shape of the door handles. c) The dashboard design. d) The color of the car.

a,b

Meteorologists are tracking a hurricane approaching the East coast of the United States. Which of the following is a limitation of using computer simulations to model this real-world event? a) Computer simulations require large amounts of processing speed and memory. Therefore the simulation is not available to use by the general public. The simulation is only available to meteorologists. b) Computer simulations can be designed and used after the real-world event, in this case of a hurricane, has occurred. c) Computer simulations require generalized constants about the real-world event, such as rainfall, wind, and currents, in order to run. d) Computer simulations require that all input parameters cannot be changed.

c

Which of the following does NOT describe the process of procedural abstraction? a) A named sequence of instructions that has a specific and limited function. b) A mental model of what we want a program to do. c) The reduction of a particular body of data to a more simplified model of the whole. d) In concept, each method should either have its behaviors encapsulated internally to a specific object or be widely usable.

c

Which of the following is NOT a reason computers use hexadecimal? a) Hexadecimal is a natural progression from binary. b) Hexadecimal is convenient and brief. c) Hexadecimal shows no relation to the binary. d) Hexadecimal is an easy way to express word size.

c

Which of the following statements is NOT true about high-level and low-level programming languages? a) High-level language must be translated into low-level language before computers can understand it. b) It is easier to debug a program written in a high-level language than one written in a low-level program language. c) Low-level languages provide fewer abstractions than high-level languages. d) Programs written in a high-level language are generally more difficult for programmers to understand than programs written in a low-level language.

d

Which of the following statements are TRUE? Select TWO answers. a) Every programming problem can be solved. b) Approximate solutions can be used when a problem takes too long to solve. c) A heuristic should only be used to solve a problem if an approximate solution is acceptable d) Heuristics are always helpful.

B and C are correct

Consider the following pseudocode. counter < 5 Total < 1 REPEAT counter TIMES total< total + 2 DISPLAY total Which of these best describes the results of running the code below? a)The number 10 is displayed. b) The number 11 is displayed. c) The number 13 is displayed. d) The number 32 is displayed.

B is the correct answer

Which of the following could be used if you want a computer to implement an algorithm that you have created? Select TWO answers. a) Natural language. b) Pseudocode c) Visual programming language d) Textual programming language

Choices 'C' and 'D' are the correct answers. Textual programming languages, such as Java and Python, or a graphical programming language, such as SNAP or Scratch, are required if you want a computer to carry out the algorithm you are considering,

Which of the following are true statements about run time? Select TWO answers. a) There is always a way to solve a problem in a reasonable amount of time. b) Reasonable run time is determined by counting the number of steps an algorithm takes to solve a problem. c) Two algorithms can solve the same problem using very different run times. d) Reasonable run time can be defined by individuals writing or using a program, and thus might vary from person to person.

Programmers determine whether or not a runtime is "reasonable" by counting the number of steps an algorithm takes to solve a problem. This makes Choice 'B' correct. Choice 'C' is also correct; it is possible for two programmers to solve a problem using different algorithms, and it's possible for those algorithms to vary in the number of steps.

Alice posts a key for encrypting that anyone can access. Bob uses that key to encrypt a message, then sends it to Alice. When Alice receives the message, she decrypts it using a private key. What kind of encryption process is this? a) Symmetric encryption b) Public key encryption c) Certificate authority process d) Vigenere cipher

The scenario described above is an asymmetric encryption process because different keys are used to encrypt and decrypt. This scenario is actually called a public key encryption, so Choice B is correct. Alice publishes half of her key so that anyone can send her encrypted messages, but she is the only one that can decode the messages with her private key. The other choices are incorrect.

Which of the following can be represented by a single binary digit? Select TWO answers. a) Any integer modulus 2 b) The temperature outside c) The score on a math test d) If a grade is passing or failing

a,d

In many programming environments today, one language translates the programmers' code into a different language before the computer actually executes the code. For instance, the visual programming language Alice translates your instructions into Python, then Python translates the code into machine- readable code. Python, in this situation, also relies on some C/C++ libraries for certain items, including collision detection. In this situation, which is the highest-level language being used? a) C/C++ b) Python c) Alice d) Machine code

c

Aaban and Manha are trying to simplify the following mathematical expression: 11 - 6/2 * 3 + 1 They are debating if they should start with the subtraction, division, multiplication, or addition operation. The discussion they are having is about which of the following issues? a) Sequencing b) Selection c) Iteration d) Distributive property

Choice 'A' is the correct answer, Aaban and Manha are discussing the order in which the operations should be carried out, which is sequencing,

Which of the following statements about packets is TRUE? a) Packets must be sent in order so they can be reassembled at the end host. b) Packet switching results in a sustained connection between two hosts. c) All packets must pass through a centralized router to be verified before reaching their destination. d) None of these statements are true.

None of the statements are true. Packets can be sent in any order because they contain bits explaining how to reassemble them at their destination, choice A. Packets can follow any path that is available to get to the destination, so there is no sustained connection between the start host and the end host, choice B. There is no centralized router that packets must travel through, choice C. Thus, choice D is correct!

Most of Monica's stuffed animals are worth a few dollars, but some are worth more. She decides to only sell the stuffed animals that are worth more than $7.00. She goes through the list she created of all the stuffed animals and their prices. If one is worth more than $7.00, she highlights it. Which of the following are part of Monica's algorithm? a) Iteration only b) Selection only c) Iteration and selection d) None of these

Once again, Monica needs to look through every item in a list. This is iteration. This time, however, she is picking items based on a certain criteria. This is selection. Thus, Choice 'C' is correct

In the short program above, which is best thought of as a constant? a) pi b) r c) a d) pi * r * r

a

What method would be the best way to search for an item in the list below? (6, 2, 1, 0, 3, 19, 201, 33, 17) a) Linear search because a linear search can only be used to search a sorted list. b) Linear search because a linear search can be used to search any list. c) Binary search because a binary search can be used to search a sorted list. d) Binary search because a binary search can be used to search any list.

B is correct

You observe that function, when given an input of 2 returns an output of 4. An input of 4 returns and output of 16. Which of the following are possible mathematical representations of this function? Select TWO answers, a) a(x) = 2x b) b(x) = 2^x c) c(x) = x^2 d) d(x)= 4/x

Choices 'B' and 'C' are the correct answers.

A constant is a special type of variable sometimes used to represent a piece of information in a computer program. Which of the following choices is the best situation for using a constant in a program? a) To represent a player's current score in a computer game. b) To represent the number of times a loop has executed. c) To represent the name of the leader in a bowling app. d) To represent the maximum number of lives a player can have in a game.

d

Consider the following: 0110 1011 0010 1011 This sequence represents a) A number b) Data c) Instructions for the computer d) Something that depends on the context in which it is used.

d

The following image shows four different representations of data. Which representation is at the lowest level of abstraction? a b) Hexadecimal digits: #7F4FC9 c) Characters/word: PURPLE d) Binary digits: 0111 1111 0100 1100 1001

d

Which of the following scenarios would NOT require a type of simulation? a) Two students want to know what percent of their district is in favor of starting school an hour later. b) A basketball coach wants to determine the odds of being placed in a certain part of a tournament bracket so he can prepare his team for a specific opponent. c) A researcher is working on a new type of jet that is louder than most airplanes. He needs to determine if the noise of the jet is harmful to passengers on board. d) A city planner needs to determine which parts of the city used the most water last quarter.

d

Eric reads an article about a problem in computer science. He reads that there is an algorithm to solve the problem, but the algorithm only works for some of the possible inputs. It's been proved that there is no algorithm that works for the other inputs. What kind of problem is Eric reading about? a) Undecidable b) Unreasonable c) Unsolvable d) Undetermined

Choice 'A' is the correct answer. An undecidable problem is one for which a single algorithm cannot be created to always lead to a yes or no answer. The problem that Eric is studying fits this description perfectly; an algorithm works for some of the possible inputs, but for others there is not an algorithm that can be used to reach a decision.

Consider the following lists. 1. list1 [2,4,5,7, 11,33] 11. list2 [-2,-1,0, 1, 2, 3, 4, 5, ..., 900, 901, 902] III. list3[-12,4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,0] For which of the following lists would a binary search be more efficient than a linear search? a) II only b) III only c) II and III only d) I, II, and III

Choice 'A' is the correct answer. Binary searches are used to search through sorted lists. The efficiency of the binary search increases as the size of the list increases. Therefore, the only list that is both large and sorted is list2.

Which of the following statements is the most true concerning general programming languages? a) Most general programming languages are comparable when it comes to being able to express an algorithm. b) General programming languages are typically developed to solve specific problems in certain domains or areas. C) By definition, all general programming languages use the same syntax. d) The same algorithm implemented in two different general programming languages will have nearly identical run times.

Choice 'A' is the correct answer. Nearly all general programming languages are similar in the fact that they can be used to express an algorithm. Each language may be able to express the algorithm in different ways, but at least the algorithm can be expressed.

A salesperson is given a list of cities and the distances between them. The salesperson has to visit each city exactly once and then return to the first city. What is the shortest possible route the salesperson could take? To find the exact answer, a computer program would have to create every possible route, calculate the lengths of all of them, and then to find the shortest route. This clearly isn't efficient when there are many cities the salesperson must visit. Alternatively, a computer could use this algorithm: 1. Select a city to start. 2. Select the closest unvisited city. 3. Repeat step 2 until all cities have been visited. 4. Return to first city. This algorithm won't always return the shortest route, but the route it returns can be considered "short enough". What is this algorithm an example of? a) An abstraction b) A heuristic c) An unsolvable problem d) An unreasonable problem

Choice 'B' is correct.

Stan is working on a procedure that takes an integer as an input and returns true or false depending on certain criteria. He tests his procedure with a variety of inputs and notices that his algorithm only gives the correct answer when the input is negative or zero. He cannot come up with an algorithm that works for all integers. What kind of problem does Stan have? a) Unreasonable b) Undecidable c) Unfixable d) Undefined

Choice 'B' is correct. An undecidable problem is one for which there is no algorithm that results in a yes-or-no answer for every possible input. Since Stan cannot come up with an algorithm that always produces a yes or a no, his problem is undecidable.

Consider the code below: numbers < [12, 17, 15, 72, 3] big < 0 FOR EACH number IN numbers { IF(number>15) big < big +10 ELSE big < big - 10 } display (big) Line 5 is BEST described as: a) sequencing b) selection c) iteration d) algorithm

Choice 'B' is the correct answer. Selection refers to a boolean expression that is used to determine which subsequent operations are to be carried out. As line 5 is a boolean expression telling us which numbers to select.

The following procedure was written to implement an algorithm whose purpose is to return the sum of all the even numbers in a list. This code will regularly be used by a company and possibly modified in the future. PROCEDURE SumEm (numlist) { s<0 FOR EACH num in numlist { IF (num MOD 2 = 0) { S<S + num } } RETURN S } From a programmer's perspective, it would make sense to make a few improvements to this code. Which of the following is the LEAST needed improvement in order to add clarity to this code? a) Change the name of the procedure from sumEm to sumEvenNumbers b) Change the name of the element from num to evenOrOddPositiveNumber ; c) Change the name of variables to sum d) Add comments to describe the purpose of this procedure and explain its parameter

Choice 'B' is the correct answer. The name of the element is num which is short but descriptive enough in this case, evenOrOddPositiveNumber is much too long a name for a variable because it would be time consuming and error prone to retype each time you need to use it in the code.

By using a password that contains a mixture of 8 letters and numbers, a hacker could crack your password in a little over 16 minutes. However, by adding two more letters or numbers, it increases the time to about 15 days! By adding the @ symbol to your password, the time is increased to almost 1628 years! Which of the following is TRUE regarding passwords and the length of time it takes to crack them? a) As you increase the number of characters in your password the ability to crack the password is solvable. b) As you increase the number of characters in your password the ability to crack the password is unsolvable. c) As you increase the number of characters in your password the ability to crack the password becomes more unreasonable to solve. d) As you increase the number of characters in your password the ability to crack the password becomes more reasonable to solve.

Choice 'C' is correct

The game of tic-tac-toe has long been explored by computer scientists. The game has a small finite list of permutations, but does not contain an algorithm for guaranteed victory. How might you describe the algorithm used by Al to play the game? a) Computer because a win state is always possible. b) Incomplete because a win state cannot always be obtained. c) Decidable because the algorithm can always answer whether or not the game is winnable given the state of the board. d) Undecidable because of the possibilities of ties.

Choice 'C' is correct The ability for the game to end in three different possibilities is important to consider. The wording of Choice 'C' phrases it as winnable or not. This forces the algorithm to have two choices "win" vs "not win". Due to the finite number of choices, the algorithm can determine whether the game is still winnable on any given turn. This makes it decidable.

Algorithms need to run in a "reasonable" amount of time in order to be considered practically useful. Which of the following BEST describes how programmers determine if an algorithm takes a reasonable amount of time? a) Programmers time how long it takes a program to execute using multiple inputs. An average time is calculated after several trials. b) Programmers count the number of lines of code in an algorithm. c) Programmers count the number of steps an algorithm takes and compare that number to a polynomial function of the size of the input. d) Programmers run a standard base algorithm at the same time as their algorithm and note which one finishes executing first.

Choice 'C' is the correct answer Run time is determined by first counting the number of steps an algorithm takes and then comparing that number to a polynomial function of the size of the input, as described in Choice 'C.

Why was IPv6 introduced as the new version of the Internet Protocol? a) With only 32 bit IP addresses, the older version could not support the large number of devices connecting to the internet. b) The new version features advanced techniques to redirect network traffic, making the Internet faster and easier to use. c) While not available everywhere, the new version enables devices to access the Internet using personalized IP addresses. d) The new version categorizes IP addresses, which makes them easier to remember and locate.

Choice A is correct. Each device that connects to the Internet receives an IP address. With the old version of Internet Protocol (IPv4), each address consisted of 32 bits. However, when more and more computers started connecting to the internet in the late 1990s, it became clear that the 32-bit addresses would soon be gone. IPv6 features 128-bit addresses. This will allow many more devices to access the internet.

How are protocols like HTTP, SMTP, and IP created? a) Independent contractors hired by companies to create protocols b) A worldwide group of volunteers to draft, revise, and publish protocols c) Individuals make their own protocols for personal use d) Individuals make their own protocols that occasionally catch on and are used by most of the internet

Choice B is correct. HTTP, SMTP, IP and other protocols are created by the Internet Engineering Task Force. The IETF is a large group of volunteers from around the world who write and debate protocols for the Internet. Much consideration is given to each protocol because these standards must be used across the entire Internet.

Which of the following is a setback of the trust model of the Internet? a) It's easy for Internet users to get away with crimes online. b) Systems with new certificates will struggle to be accepted by other users' systems. c) There is no monitoring of suspicious behavior on untrustworthy websites. d) None of these are actual setbacks of the trust model.

In a hierarchial public key system, there is a certificate authority (CA) that verifies each system's trustworthiness. There are smaller certificate authorities under each larger one that verify smaller websites. In a trust model, however, users verify other users instead of waiting for verification from a CA. Without a certificate authority, a new system will struggle to make connections at first, since most other users will refuse to work with a system that has never been verified. This makes choice B correct. Choices A and C might be true, but they do not have to do with the trust model.

The following image shows different representations of data. Which of the following is true about the representations of data? the image with purple red green blue a) All four represent the same hexadecimal data b) All four do not represent the same hexadecimal data c) The color representation is the most meaningful d) The representations are all at the same level of abstraction

b

Many cyber security threats have human and software components. Which of the following situations describes the human component of phishing? a) A hacker identifies a company to impersonate, then develops a believable email to distribute to a mass address list. b) A hacker writes a program that erases the contents of a hard disk but packages it as a computer game. c) A hacker creates an email attachment that automatically sends malicious emails to an entire address book when opened. d) A hacker sets up a system where information collected from a malicious email is automatically inputted into a spreadsheet of private data.

Phishing is the act of sending an email that looks official and asking for personal information. These emails often ask for credit card or social security numbers. Choices A and D both refer to phishing, but the human component of phishing is choice A. Before a hacker can begin a phishing scheme, he or she must select a company to impersonate and write a believable email. If the email is not believable, the scheme will not work. Choice B describes a Trojan horse, a program that is malicious but appears to be harmless and choice C refers to an email virus - a program that wreaks havoc when attached to an email.

Which of the following statements are true of procedures? Select TWO answers. a) Procedures must return a value (a number, text, Boolean, etc.). b) Updating code is easier if procedures are used for repeated parts of the program. c) A procedure must be called more than once in order to be useful. d) Procedures make programs less complex by reducing identical code.

b,d

How does the hierarchical architecture of the DNS help the system scale? a) The architecture makes it easy to get a new domain name. b) The architecture involves procedures for new IP addresses. c) Domain names have a set structure, making them easy to organize and manage. d) Host names can be found in a database that can be distributed over many servers.

A database of all the domain names being used is stored across many servers. Since the DNS is not being stored on one server, new domain names can be added all the time without affecting performance. This makes choice D correct. Choices A, B, and C are all false.

A hacker uses hundreds of different IP addresses to overrun a bank's website with requests. This effectively shuts down the website and prevents any Internet users from accessing it. Which of the following is the name for this kind of attack? a) DNS spoofing b) 404 error c) Denial of service d) Distributed denial of service

A denial of service attack (DoS) is an attempt to shut down a website or server by flooding it with requests. If the requests come from hundreds or thousands of IP address like in this example, the attack is called a distributed denial of service attack (DDoS). This makes choice D correct.

Which of the following statements is TRUE regarding Internet protocols? a) The Internet is the same thing as the World Wide Web b) HTTP is a protocol primarily used for electronic mail. c) When a request is made by a client computer, HTTP ensures that the client is connected to the requested web page for the entire duration it's being viewed. d) All of the above are false.

Choice A is false; the World Wide Web is an application that runs on the Internet that allows users to view web pages and access information. They are NOT the same thing. Choice B is also false; the protocol for electronic email is predominantly SMTP, not HTTP. HTTP is a protocol that enables browsers and servers to communicate. Choice C is false because HTTP is a connectionless protocol. Each new request gets its own connection, and once the request has been met, the connection is gone. Thus, choice D is correct.

Caesar Cipher is an older and since outdated encryption technique used by Julius Caesar to "hide" messages he sent to his troops. Using Caesar Cipher, each letter in the alphabet is translated to a letter with the same given offset from the original letter. Characters that are not A-Z remain as is. For example, if the message is HI ZOE and the offset is 2, then the encrypted message is JK BQG, since the letter "J" is two letters after "H" in the alphabet, and "K" is two letters after "I" in the alphabet, etc. Notice that "Z" is at the end of alphabet and the offset is 2, the algorithm has to wrap back around the beginning of the alphabet so that "Z" translates to "B". Suppose you want to encrypt the following message: REMAIN HOME. Of the following, which would be a potential encrypted message using Caesar Cipher? a) UHPDLQ KRPH b) TGPBKP JPQG c) SFNCKO IPNF d) PFLBHO INND

Choice A is the correct answer. UHPDLQ KRPH is the correct encrypted message if the offset is 3. Each of the corresponding letters in the original message REMAIN HOME is translated to three letters after that letter in the alphabet. For example, the third letter after "R" is "U", and the third letter after "E" is "H". This offset is used for every character in the original message. Choice B is an incorrect answer. The first couple of letters are using an offset of 2. However, that is not the case for every letter in the encrypted message TGPBKP JPQG. Using Caesar Cipher, all letters are translated using the same offset. For example, the first two letters "R" and "E" use an offset of two to translate to letters "T" and "G". However, the third letter "M" should translate to "O" but the encrypted message has the third character "P". Choice C is an incorrect answer. The first few letters are using an offset of 1. However, that is not the case for every letter in the encrypted message SFNCKO IPNF. Using Caesar Cipher, all letters are translated using the same offset. For example, the first three letters "R", "E", and "M" use an offset of one to translate to letters "S", "F", and "N". However, the fourth letter "A" should translate to "B" but the encrypted message has the fourth character "C". Choice "D" is an incorrect answer. In this choice, the offset seems to go between +1 and -1. Using Caesar Cipher, all letters are translated using the same offset. For example, the first letter "R" uses an offset of -1 to translate to letter "P", but the next letter "E" uses a +1 offset to translate to letter "F".

New websites are being created every day, yet Internet users are still able to navigate the web and access information at the same speed. Which of the following makes this possible? a) Redundant routers b) Hierarchical DNS c) Open standards and protocols d) Fault tolerance

Choice B is correct. The hierarchical structure of the Domain Name System allows new domain names to be added all the time. Domain names are stored on multiple servers, making it easy for the Internet to grow without becoming unmanageable. Choice A is incorrect. Redundant routing is useful because it ensures that packets can still be sent and received even when part of a network is down. It does not, however, make the addition of new websites possible. Choices C and D are also incorrect; neither of these make the addition of new websites possible.

The Open Systems Interconnection (OSI) is a conceptual model whose purpose is to make networks more manageable. Its objectives include allowing for more portable hardware and software integration, the creation of standard interfaces that would allow manufacturers of different systems to interconnect their equipment and the creation of a model that would be used world-wide. There are seven layers to the OSI. The lowest - or first - layer allows a contiguous sequence of bits to be transmitted through the network. Which of the following layers is the first layer of the OSI? a) The data-link layer b) The physical layer c) The network layer d) The transport layer

Choice B is correct. The physical layer provides the hardware means of sending and receiving data on a carrier network. Choice A is incorrect. The data-link layer sets up links across the physical network putting packets into network frames. Ethernet is the main data link layer in use. Choice C is not correct. The network layer handles the addressing and routing of the data. IP is the network layer for the Internet. Choice D is incorrect. The transport layer link manages packetization of and delivery of data and checks for data errors when the packet arrives at its destination.

Which of the following statements about TCP/IP is FALSE? a) TCP/IP is the most widely used standard for packets and routing. b) TCP/IP is exactly two sets of protocols (TCP and IP) c) IP is a set of standards for routing and transferring information on a network. d) TCP is a set of standards for how computers communicate with each other.

Choice B is false; TCP/IP is actually called a "suite" of protocols because it contains many different protocols for using the Internet. The main protocols are TCP and IP. This suite is the most commonly used today, so choice A is true. The IP standards handle addresses and routing information, so choice C is true. The TCP standards handle the procedures that computers use to communicate, so choice D is true.

A domain name consists of several domain labels separated by dots. Which of the following statements about domain name labels is FALSE? a) Every domain name ends with a top-level domain label. b) The hierarchy of domain name labels descends from left to right. c) The left most label of the domain name identifies the server. d) There is virtually no limit on the number of subdomains in a domain name.

Choice B is the false statement. Each domain name is broken up into labels that are separated by dots. The top tier of labels is on the right (the .com, for example). Each label on the left is a second level domain. This means that choice A is true; the top-level domain labels and every domain name. The most popular examples are .com, .net, and .org. Choice C is also true; the leftmost label is usually "www", which would identify a World Wide Web server. Or that label might be "mail", signifying an email server. Choice D is also true; domain names can have a large number of subdomains under the Domain Name System.

Which of the following statements about security on the Internet is FALSE? a) Many methods of cybersecurity rely on cryptography. b) The trust model of the Internet ensures total security. c) There are hardware and software components of cybersecurity in addition to human components. d) The Internet is designed to scale so that more systems and networks can join at any time.

Choice B is the only false statement here. The trust model of the Internet refers to computers trusting entities that have been trusted by others. Clearly this does not eliminate the risk of breaching cybersecurity. The other choices are all true statements. Public key encryption and symmetric encryption are two very common cybersecurity techniques that rely on cryptography (choice A). Cybersecurity is implemented as hardware (cybersecurity measures built into the processing chip), software (antivirus programs), and human (passwords) components as in choice C. Choice D is also true; the Internet was designed to scale, meaning that it can increase tremendously in size and still work as intended.

Which of the following are potential effects of the growth of cyber warfare? Select TWO answers. a) The differences between countries will become more pronounced. b) National militaries will become stronger and more unified. c) The sources of cyber-attacks will be difficult to identify, allowing for many more attacks in the future. d) Countries with less resources will make a larger impact than they have in the past.

Choice C is a potential effect of cyber warfare. Depending on the experience of the level of the perpetrator, it can be extremely difficult to identify a culprit for an online crime. This fact could encourage others to commit cyber warfare with little worry of being caught. Choice D is also true; cyber warfare is possible as long as one has an Internet connection and some programming skills. This means that countries with few resources could potentially make a bigger impact than in the past. Choice A is incorrect; many people view cyber warfare as an "equalizer" because it gives countries with almost no resources the opportunity to fight. Choice B is also incorrect; cyber warfare is accessible for anyone with the right skills. This means that international warfare will not be limited to national militaries. Anyone will be able to fight.

What is the primary reason that routing on the Internet is redundant? a) Many routers were established before standards for routing existed. b) There is no monitoring to make sure that repeated paths don't exist. c) Networks are still available in case of a path or router failure. d) None of these.

Choice C is correct. Internet routing is redundant so that communication doesn't end if one outer fails. This backup system ensures that information will always be available to travel across networks. Choices A, B, and D are all incorrect.

Which of the following statements about cybersecurity is true? a) The domain name system (DNS) is designed to be secure. b) Open standards are part of the reason why cryptography is not secure. c) Certificate authorities operate based on the trust model. d) Public key encryption is symmetric.

Choice C is the correct answer. Certificate authorities operate on a trust model. This means that if an encrypted key has been trusted by many devices, the next device to use that key will also trust it. Choice A is false; by design, the DNS is not completely secure. Choice B is also false; open standards for cryptography create good guidelines for online security. Choice D is false as well; with public key encryption, the sender uses a key to encrypt a message and the receiver uses a different key to decrypt. This is an asymmetric encryption method.

A hacker changes a record so that the DNS maps an incorrect IP address with a domain name. Which of the following is the name for this kind of DNS attack? a) DNS phishing b) DNS ID hacking c) DNS cache poisoning d) None of these

Choice C is the correct answer. DNS cache poisoning is the act of making a DNS server cache incorrect information. A common trick of hackers is to get the DNS to associate the incorrect IP address with a domain name, like in this question. For example, a hacker might want any query about a bank's website to be directed to his or her computer.

Which of the following statements about packets is FALSE? a) Each packet of information is sent independently. b) It is possible that each packet might take a completely different path to the end host. c) The packet does not contain information about the sender's IP address. d) Packet switching results in a decentralized network.

Choice C is the correct answer. Each packet does contain information about its origin a destination. The Internet utilizes a packet switching system where information is split into small packets before being sent to the end host. Each packet is sent independently and each could potentially take a completely different path (this makes choices A and B true). This kind of system is called a decentralized network; instead of every single packet of information traveling through a central hub, each packet can take its own route. This ensures that the Internet will still work if one network or router isn't working correctly. So, choice D is also true.

Ransomware is a relatively new form of attack on a computer system. A ransomware attack is when an individual or group of individuals targets an organization's server and is able to use a sophisticated form of encryption to lock down the organization's files. Effectively, the organization cannot gain access to their own data, causing major disruptions. The term "Ransomware" comes from the fact that the organization is asked for money in exchange for being granted access to their files. Of the following, which is the LEAST effective way for an organization to protect against Ransomware? a) Make sure that its operating system software updates are implemented on a frequent basis. b) Install anti-virus software on its servers. c) Make frequent backups of its data and store the backups online on the same server as the original data. d) Educate its employees about cybersecurity concerns and how to proactively address them.

Choice C is the correct answer. The first part of the statement is a valid and important step that an organization should take; they should back up their important data on a frequent basis. However, the second point is what makes this choice inferior. Since a ransomware attack locks down the files on a server, keeping the backups on the same server as the data itself would defeat the purpose of the backups and make them vulnerable to the ransomware attacks as well. Backup files should be stored at an offline location separate from the organization's main network. Choice A is an incorrect answer. Making sure that updates to the operating system are implemented on a frequent basis is a very important way to mitigate viruses. Operating systems are continually being patched to make the systems less vulnerable. Choice B is an incorrect answer. Anti-virus software is a major line of defense to fight off all types of viruses, including ransomware. It is important to keep the anti-virus software up-to-date to make sure that it is fighting off the latest threats. Choice D is an incorrect answer. All organizations should educate their employees on cybersecurity issues, especially those dealing with phishing, viruses, and ransomware.

Which of the following statements is true regarding the networks that make up the Internet? Select TWO answers. a) If one network crashes, all other networks are affected. b) The World Wide Web is one of those networks that is connected to the Internet. c) Different types of networks can be connected in order to transfer data and communicate. d) All devices that are connected on a network use the same protocol.

Choice C is true; routers can be used to connect different types of networks to create an internetwork. The routers act as translators between the networks and allow for communication between devices. Choice D is also correct; any device connected to a network (such as an Ethernet or WiFi network) must use the protocol specified by the network so that all devices behave the same way. Choice A is false; the Internet is extremely redundant, meaning that if one network is down, the data will have many other paths to travel. Choice B is also false; the World Wide Web is an information system that runs on the Internet; it's not a network.

The Domain Name System (DNS) has a hierarchy that improves redundancy and helps the systems on the Internet scale appropriately. Which of the following statements is NOT true about the DNS? a) The responsibility of a DNS server is to take the domain name from a URL and convert it into a valid IP address. b) The top-level domains in the DNS hierarchy are the extensions after the last period in the domain name, such as com, edu, org, etc. c) Top-level domains in the DNS hierarchy can be organizational or geographical. d) Possible valid domain names for XYZ Corporation include xyzcorp.com, net.xyzcorp, and xyz.com.corp.

Choice D is the correct answer, since it is false. Domain names must end with valid extensions, called top-level domains. Examples of common top-level domains are com, net, edu, and uk, but there are many others. The top-level domains follow the last period contained in the domain name. xyzcorp.com is a valid domain name, but net.xyzcorp and xyz.com.corp are invalid names. Choice A is an incorrect answer, since it is true. The main purpose of a DNS server is to convert the domain name from the web address into an IP address which identifies the appropriate computer. Choice B is an incorrect answer, since it is true. The top-level domains in the DNS hierarchy are the extensions after the last period in the domain name. The DNS root zone servers are responsible for identifying the appropriate DNS servers responsible for each of these top-level domain names. Choice C is an incorrect answer, since it is true. Top-level domains in the DNS hierarchy can be organizational, such as com, gov, and edu. Top-level domains can also be geographical, such as the two-character extensions used by coutnries: us, mx, and uk.

Which of the following is an example of a subdomain of albert.io according to the domain name system (DNS)? a) albert.io/test-prep b) albert.co.uk c) albert.com d) contact.albert.io

Choice D is the correct answer. Subdomain names appear before the main domain name. In our example, contact is the subdomain and albert.io is the main domain. Choice A is incorrect because this is an example of a subdirectory. Choice B is incorrect because the top-level domain name (TLDs) has been changed and is therefore a different site entirely. Choice C is incorrect because the top-level domain name (TLDs) has been changed and is therefore a different site entirely.

Each packet being routed around the internet contains header information about the packet itself, and it also contains part of the file being transferred (which is called its payload). Imagine that you are sending an image of a basketball player from computer A to computer B across the internet. Of the following, which information would be contained in each packet's header? Select TWO answers. a) The color of the upper left pixel of the image. b) The IP address of the destination computer. c) The sequence number of the packet in relation to all the other packets of the image. d) The name of the basketball player represented in the image.

Choices B and C are the correct answers. The image will be broken up into many different packets and put back together on the target computer. Each packet will need to keep track of the destination computer's IP address in order for routers to send the packets over the internet to the correct destination. This information will be part of the packet's header. Packets can be sent along different paths and arrive in any order at the destination computer. Therefore, it is necessary for each packet to contain a sequence number, so that the packets can be reassembled in the correct order on the receiving computer. Other information, such as the IP address of the sending computer, is also stored in the header of each packet. Choice A is an incorrect answer. The pixel color is part of the actually data of the image itself. This information is not part of the header, but is instead part of the packet's payload. Choice D is an incorrect answer. The name of the basketball player represented in the image may or may not be part of the image itself. If so, it would be part of the packet's payload. It would definitely not be part of the header of each packet.

HTTP is an example of an open standard of the Internet. What are the benefits of open standards like HTTP? Select TWO answers. a) They allow individuals to make changes to the standards for their own personal use. b) They allow devices and applications across many networks to work together and communicate. c) They are always revised by Internet users around the world. d) They are open for interpretation, meaning that everyone can use them in a different way.

Each network connected to the Internet is owned by a separate entity - a government, business, or individual. In order for all of those separate networks to work together, there needs to be a set of common standards that they all follow. Therefore, choice B is correct; anyone can help create or revise the open standards The input they receive from Internet users around the world ensures that the standards are appropriate and useful. Once the standards are revised, they are not open for interpretation, and individuals cannot change them for their own personal use. This makes choices A and D incorrect.

Which of the following best describes the basic idea of fault tolerance? a) A system that never fails. b) If part of the system fails, the operation continues without interruption. c) A program that does not allow inputs out of a range given by the programmer. d) A program that does not allow loss of precision.

Fault tolerance is the idea that a system can continue running even if part of it fails. The Internet uses redundancy to achieve this principle (if one network is down, there are other networks that routers can use to pass on information). This makes choice B correct.

The new version of the Internet Protocol, IPv6, allows for IP addressed that are 128 bits long. How many possible IP addresses are available with IPv6? a) 2^127 b) 2^128 c) 8^128 d) 2^128 - 1

For each bit in the address, there are two choices: 0 or 1. Thus to find the total number of available addresses, we need to multiply 2 by itself 128 times, since there are 128 numbers in the address. This makes choice B correct.

Which of the following standards created by the Internet Engineering Task Force (IETF) is always required? a) HTTP b) SMTP c) IP d) TCP

IP (or Internet Protocol) is the foundation of the connections made on the Internet. This is the protocol that allows devices to connect to each other and to different networks. Without it, there would be no Internet. This makes choice C correct. The other protocols listed in this question are extremely common, but not required. For example, TCP can be used to ensure that a message is delivered reliably, but there are other protocols that could be used instead. IP, however, is necessary in order to transfer packets from one place to another.

Many networks are set up using a hierarchical architecture to create a "backbone" network. In this system, several connected routers act as the backbone and many similar LANs are connected to the backbone. This much different than having a system where every router is connected to every other router. What are the benefits of the hierarchical approach to setting up a network? Select TWO answers. a) It allows more people to access the Internet. b) It decreases the total number of routers needed in the network. c) It decreases congestion in the network. d) It makes the process of transferring data much more efficient.

Imagine you are trying to get a piece of information to a different computer in the hierarchical network. Your data could potentially only hit two routers; once when the data reaches a backbone router and a second time when it reaches its destination. This is much more efficient when transferring data from router to router until it happens to get closer to the destination choice D. It also decreases traffic in the network, since the data doesn't have to travel through as many routers choice C. Choices A and B are both false; the hierarchical structure does not affect how many people can connect to the Internet and it may or may not change the number of routers in the network. Therefore, the correct answers are choice C and D.

Which of the following scenarios would breach the security of a message encrypted with a public key? a) If the encrypted message was intercepted by a third party. b) If the holder of the private key forgot or destroyed the private key. c) If a third party accessed the private key. d) If the public key was made known.

In a public key situation, there are two parts of an encryption key: the public part that anyone can access for encryption and the private part that only one person can access for decryption. Since anyone can access the public key, it would not breach security if the public key was made known as in choice D. Since only the person with the private key can decrypt the message, choice A is also incorrect. If the holder of the private key forgets or destroys it, as in choice B, there is no security breach. The person would forever be unable to read the encrypted messages, but no one else would be able to read them either. The security breach occurs in choice C when a third party figures out the private key. This would make any encrypted message accessible to the third party. Thus, choice C is correct.

Andrew uses an application to track how long it takes a packet to travel from his computer to a Wikipedia server. Which of the following is he measuring with this application? a) Bandwidth b) Latency c) Number of packets d) Router speed

Latency is the time it takes for data to travel from one host to another. The application that Andrew is using is measuring this time, thus choice B is the correct answer. Bandwidth choice A refers to the rate at which data is transferred in a set amount of time. Number of packets choice C and router speed choice D are not measured with this application.

Many hardware, software, and human components contribute to the security of the Internet. Which of the following is NOT one of the ways that cybersecurity is implemented? a) Through hardware components, such as protections built into the processing chip. b) Through software components, such as antivirus programs that detect and prevent viruses. c) Through hardware components, such as passwords for secure websites. d) Through human components, such as security questions when a password is forgotten.

Passwords are an important part of cybersecurity, but these are a human or software component, not a hardware component. This makes choice C the only incorrect implementation of cybersecurity. The other choices are all accurate ways that cybersecurity is implemented online.

A new device is given an IP address and added to a network so that it can access the Internet. Large amounts of files are uploaded and downloaded on this new device, but other users who were already online do not experience any difference in performance. Which of the following enables this phenomenon? a) Redundant routers b) Hierarchical DNS c) Open standards and protocols d) Fault tolerance

Routers on the Internet are redundant, meaning that there is always more than one way for data to be transferred from one host to another. Imagine an Internet where this is not the case: every packet of information must travel along the same path. Now imagine that a new device is added to a network and many new files are being uploaded and downloaded. That one path that everyone has to use is now clogged with significantly more packets. Adding new devices in this version of the Internet would be aggravating for users who are already connected. Luckily, routers are redundant, so that new device can upload and download data without making an impact on traffic. This makes choice A correct.

Which of the following protocols is primarily used to establish a secure connection between browsers and servers so that no data is lost? a) HTTP b) SMTP c) SSL/TLS d) TCP/IP

SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) use encryption and other techniques to ensure that third parties are not able to access data being transferred between browsers and servers. Thus, choice C is correct. HTTP choice A is a protocol that helps browsers and servers communicate. SMTP choice B is a protocol primarily for electronic mail. TCP/IP choice D is a large suite of protocols for using the Internet.

Which of the following are benefits of the trust system of the Internet? Select TWO answers. a) It is less expensive to implement that other alternatives. b) It enables cooperation between two online entities. c) It decreases the amount of traffic online. d) It eliminates the risk of viruses and worms.

Since the trust model relies on Internet users trusting other Internet users and not one centralized system that approves everyone, it is relatively inexpensive. This makes choice A correct. By nature of the system, the trust model also enables cooperation as in choice B. Choices C and D are both incorrect.

Which of the following do HTTPS and SSL procedures ensure? Select TWO answers. a) That the identity of the server involved in an interaction can be trusted. b) That every download will be free of viruses. c) That any messages being sent are encrypted and thus secure. d) That passwords, credit card numbers, and any other private information will not be "remembered" by a website.

The HTTPS and SSL procedures promise two things: that the identity of any server involved in a transaction will be verified choice A and that any message being transmitted will be encrypted and secure choice C. The other choices are not guarantees of the HTTPS or SSL protocols. Therefore, choices A and C are the correct answers.

Which of the following statements are true of the Internet Engineering Task Force (IETF)? Select TWO answers. a) One of the IETF subcommittees determines where to place underwater fiber optic cables. b) The most important work of the IETF is to create and maintain protocols like HTTP and SMTP. c) The IETF is completely made up of volunteers from all over the world who do not need to attend meetings in person to participate d) The IETF is a government sponsored organization formed in order to monitor Internet standards

The Internet Engineering Task Force's main goal is to create and maintain standards for the Internet, as stated in choice B. To make their decisions, the IETF uses a mailing list to ask members for input. There are no required meetings to attend and all participants are volunteers, making choice C also correct. The IETF was created by the US federal government, but it has since become a non-profit organization as part of the Internet Society. Therefore, choice D is incorrect. Choice A is also incorrect, this is not one of the duties of the IETF.

Which of the following is the BEST description of what a certificate authority does? a) Issues digital certificates that certify that a password is correct. b) Issues digital certificates that certify the ownership of public keys. c) Issues digital certificates that certify access to a wireless network. d) None of these.

The certificate authority (CA) issues the digital certificates if it verifies that the public key is owned by the correct entity. This allows browsers to trust certain public keys. This makes choice B correct. The other choices are false.

An end-to-end architecture creates a network that is which of the following? Select TWO answers. a) Complex b) Reliable c) Open d) Unpredictable

The end-to-end architecture places all functions at the beginning and end nodes of a network, not in the middle. For example, if you were to send a file to another person, the error checking on the file would occur at your computer and the destination computer, but no where in between the two hosts. This makes the network "neutral" because it does not tamper with the data being transferred. This system creates a network that is reliable; error checking and other function must happen at each host (choice B). It also makes the system more open; the network is not clogged with functions (choice C). End-to-end architecture is simple not choice A and predictable not choice D.

An end-to-end architecture creates a network that is which of the following? Select TWO answers. a) Complex b) Reliable c) Open d) Unpredictable

The end-to-end architecture places all functions at the beginning and end nodes of a network, not the middle. For example, if you were to send a file to another person, the error checking on the file would occur at your computer, but no where in between two hosts. This makes the network "neutral" because it does not tamper with the data being transferred. This system creates a network that is reliable; error checking and other function must happen at each host (choice B). It also makes the system more open; the network is not clogged with functions (choice C). End-to-end architecture is simple not choice A and predictable not choice D.

Which of the following is the primary characteristic of an end-to-end architecture? a) The beginning and the end of a program use similar variables and procedures. b) Instead of each device connecting to a hub to form a network, the computers are connected to each other in a line c) Specific functions are found in the two host devices, freeing up the traffic on the network between them. d) None of these.

The end-to-end principle is the idea that functions should be in the end hosts of a network instead of in the nodes of the network. For example, if you were to send a file to another device, the number of bits in the file would be checked on your computer and the destination computer, but not any of the nodes in between. As choice C states, this causes less traffic in the network. End-to-end architecture is commonly referred to as "smart hosts, dumb network". Choices A, B, and D are incorrect.

Which of the following is the primary characteristic of an end-to-end architecture? a) The beginning and the end of a program use similar variables and procedures. b) Instead of each device connecting to a hub to form a network, the computers are connected to each other in a line. c) Specific functions are found in the two host devices, freeing up the traffic on the network between them. d) None of these.

The end-to-end principle is the idea that functions should be in the end hosts of a network instead of the nodes of the network. For example, if you were to send a file to another device, the number of bits in the file would be checked on your computer and the destination computer, but not in any of the nodes in between. As choice C states, this cause less traffic in the network. End-to-end architecture is commonly referred to as "smart hosts, dumb network". Choices A and B are incorrect.

Which encryption method is widely used and why? a) Symmetric Encryption: this method is much faster to send and receive messages. b) Symmetric Encryption: this method is easier to use with SSL and HTTPS. c) Public Key Encryption: this method does not require a secure channel for exchanging keys. d) Public Key Encryption: this method is more widely available than other methods.

The great benefit of public key encryption is that anyone can encrypt messages for recipients without establishing a secure connection to exchange keys first. Symmetric encryption works well, but in order for it to work, both parties must have the same key. It's very difficult to obtain a secure channel in order to get that identical key for both parties. Public key encryption eliminates that difficulty by leaving part of the key private. This makes choice C correct. Symmetric encryption is not the most widely used method, so choices A and B are already incorrect. Choice D is also false because there are so many different kinds of encryption available to Internet users.

Desktop computers, laptops, tablets, smartphones, and other devices are made by different companies, yet they are all able to access the Internet. This has led to widespread use of the Internet from many different kinds of devices. Which of the following makes this possible? a) Redundant routers b) Hierarchial DNS c) Open standards and protocols d) Fault tolerance

The open standards of the Internet are created so that any device can communicate with other devices online. Even though each device is different, the common standards ensure that they can all access the Internet. This makes choice C correct. Choices A, B, and D also help increase Internet use, but not in the specific way mentioned in this problem.

Which of the following accurately describes the trust model of certificate authorities? a) An Internet user must trust that the public key they use is accurate. b) A list of trusted certificate authorities is created by a browser over time. c) A certificate authority trusts a public key if it has been approved by a different party. d) A certificate authority is trusted by the owner of the certificate and the party relying on the certificate.

The trust model is best described by choice D. A certificate authority is a third party that's trusted by the entity that owns the certificate and the party that wants to know if the certificate is verified. Choice B is almost correct; most browsers come with a list of trusted CAs, but they are not developed over time as this choice states. Choices A and C are both incorrect.

Alice and Bob need to exchange some private data online. To do this, Alice creates an algorithm that will encrypt and decrypt data. They secretly meet to share the algorithm, then they each use the algorithm to encrypt their messages and decrypt each other's messages. What kind of encryption process is this? a) Symmetric encryption b) Public key encryption c) Vingenere cipher d) Firewall software

This scenario is an example of symmetric encryption because both parties use the same key to encrypt and decrypt their data. This makes choice A correct. Public key encryption involves different keys for encryption and decryption, choice B. There is not enough detail to determine if the algorithm that Alice and Bob uses is the Vingenere cipher (choice C) and firewall software is not a method of encryption (choice D).

High-level computer programming languages, such as Python, C++, and Java, provide which of the following features? Select TWO answers. a) Constants, expressions, and libraries. b) Few or no abstractions c) Conversion to machine code without a compiler d) Statements and procedures.

a,d

Which of the following BEST help people understand the concept of an algorithm? Select TWO answers. a) Visual programming languages b) Pseudocode c) Natural language d) Textual programming languages

Choice 'B' and Choice 'C' are the correct answers. Pseudocode and natural language are designed to help people understand algorithms. However, a computer cannot understand either one

Which of the following statements about redundancy on the Internet are TRUE? Select TWO answers. a) Redundancy has good qualities; if several routers fail, data can still be transferred. b) Redundancy has good qualities; many devices can be added to the network without affecting traffic. c) Redundancy has bad qualities; it creates unnecessary routers in the network. d) Redundancy has bad qualities; as more and more devices are added to the network, it takes longer for data to be transferred.

Redundancy on the Internet is largely seen as a good thing. The main purpose of having redundant routers and paths between devices is stability. If one or more networks crashes, there are still many ways for data to be transferred. So choice A is correct; redundancy creates a reliable network. Choice B is also correct; since there are so many ways that data can be transferred, new devices can be added to the network without causing a major change in traffic. Choices C and D are both false.

Consider the following short program: In the program above, line 3 a- pi*r*r is a) Is a statement b) Is an expression c) Is both a statement and an expression d) Is neither a statement nor an expression

a

A process named "Stepwise Refinement" is useful when programming. What is Stepwise Refinement? a) Stepwise Refinement is a technique in which the programmer generates code using an increasingly larger scope for its variables. b) Stepwise Refinement is a top-down design process in which the programmer starts with the overall goal of the program and continually breaks down the design into sub-functions. c) Stepwise Refinement is a technique used by experienced programmers to convert actual programming code into pseudocode. d) Stepwise Refinement is a design process in which the programmer asks other programmers to walk through their code in order to make suggestions for optimizing it.

b

Before airplane pilots are allowed to fly actual planes, they spend countless hours in a flight simulator. Which of the following is NOT a beneficial reason to use the computer simulation? a) The simulation can create extreme scenarios to test a pilot's knowledge and ability to work under extreme pressure. b) Pilots can use the simulation to determine if this is the career for them. c) If during the learning process, the pilot makes a mistake, it will not destroy an actual plane or kill innocent people. d) Pilots can get familiar with the cockpit controls on a variety of different planes before flying the real plane.

b

A hospital is using simulation software to help train their nurses employees on safety regulations for their particular department within the hospital. The training is customized to the employee's job and department. An employee must complete training in one level before advancing to the next level of training. The software is designed so that employees can easily stop and start the training when desired. The hospital's database includes the following information about each nurse: • Employee name • Marital status • Job title • Safety certification level • Home address • Hospital department Which of the following two pieces of database information are less likely to be necessary for the simulation software to work properly? a) Employee name and Hospital department b) Job title and Hospital department c) Marital status and Home address d) Safety certification level and Job title

c

An online poker website offers a "Texas Hold 'Em" poker simulation and training feature that allows new poker players to practice. The software closely mimics the probabilities encountered when playing actual poker games. This software is offered free of charge and no actual money is bet when playing the hands, even though it simulated real cash games with multiple players. Which of the following are advantages for new players to use this simulation/training software instead of playing actual poker hands at a casino? I. This simulation software allows a new player to get valuable experience without losing money. II. This simulation software will guarantee that a new player will succeed when playing actual hands at a casino. III. The simulation software provides a good entry point for new players to hone their poker- playing skills. a) I only b) I and II only c) I and III only d) I, II, and III only

c

There are multiple levels of abstraction in computer hardware. Which of the following is NOT a level of abstraction in computer hardware? a) Transistors b) Memory c) Operating systems d) Motherboards

c

Which of the following statements are true of the standards of the Internet? Select TWO answers. a) Internet standards ensure that hardware and software created by different companies will be able to communicate with each other online. b) Internet standards are specific procedures and rules that are created in order to benefit the Internet community. c) Internet standards cannot be altered or removed once they are created. d) Internet standards are written by one company with little to no outside feedback.

All internet standards are created by the Internet Engineering Task Force, a group that allows members from all over the world to join and give their input on future protocols. The IETF takes members' feedback very seriously and always considers updates to the current standards is proposed. That makes choices C and D incorrect. The IETF does, however, ensure that standards create methods of communication between products from different companies (choice A). They are also focused on creating protocols that will benefit Internet users they represent (choice B). Therefore, choices A and B are correct.

Which of the following are ways that the Internet has changed the way people collaborate? Select TWO answers. a) Cloud computing allows people to work on the same document from different areas of the world. b) Word processing programs allow users to track changes, which lets people comment on each other's work. c) Video conferencing software enables people to talk to coworkers and friends. d) Conference calls help people stay connected and discuss ideas.

All of these technologies have changed the way that people communicate, but choices A and C show how the Internet has played a role in these changes. Cloud computing is a function built on the infrastructure of the Internet that allows files and other data to be stored online. Applications like Google Drive that use this function allows users to work on the same document from across the globe. Video conferencing software like Skype and FaceTime have also changed collaboration, enabling people to talk, share documents, and see other people's computer screens. Choice B is incorrect because it does not involve the internet. Choice D is also incorrect; conference calls were used for collaboration before the Internet.

Consider the code below: numbers < [12, 17, 15, 72, 3] big < 0 FOR EACH number IN numbers { IF(number>15) big < big +10 ELSE big < big - 10 } display (big) Line 3 is best described as: a) Sequencing b) Selection c) Iteration d) Algorithm

C is correct

Rowan is playing an app on his phone based on the game 20 questions. The app asks the user to think of something and then asks 20 yes/no questions to determine the thing. Rowan has played 10 times in a row where the phone was able to guess the item. Which of the following is the best answer to should the app be thought of as decidable? a) Yes, it got the solution 10 times in a row b) Yes, twenty yes/no questions allow for a very large data set of solutions. c) No, a decidable program must cover all solutions and 10 trials is not enough. d) No, a decidable program can only accept one input and cannot be applied to twenty inputs.

Choice 'C' is correct. A decidable problem should be able to answer yes or no for all inputs. The sample of 10 runs of the app is not enough to guarantee that it will work for all inputs. An undecidable may still work for some inputs and the 10 trial runs may be outliers that are covered under the vast set of possibilities the app has been designed for.

Chandler realizes that this program might be useful for people who have collections of things other than stuffed animals. When he writes his program, he leaves out details about stuffed animals and opts for more general terms. For example, instead of including "type of animal", "type of fur", "name" in the list of information, he opts for "name", "year", and "description". Which of the following computing concepts is Chandler using when he does this? a) Sequencing b) Abstraction c) Algorithms d) Efficiency Testing

Choice 'B' is correct. Chandler is removing details from the problem to make his program more functional. By removing specifics about stuffed animals, his program can now be used by people organizing collections of coins, art, antiques, or other items.

DNS stands for Domain Name System and it is used to translate domain names into IP addresses. If a domain name is college.edu, which of the following would be a subdomain of this domain? a) College.edu/admissions b) College.majors.edu c) Athletics.college.edu d) College.net

Choice C is the correct answer. A subdomain is created by entering text followed by a period in front of the domain name. A subdomain is useful when the site, such as college.edu, has major areas of content that are stored on separate computers, or when there are reasons to use a separate URL for promotional purposes. For example, if the college wants to highlight their athletics department, they may want to create a subdomain named athletics.college.edu. Athletics basically replaces the optional www subdomain. Choice A is an incorrect answer. When a slash is entered after the domain name and is followed by text, the web server is looking for a directory with that name or a file with that name. If there is an ending slash, then the web server will first look for a directory with that name and if it does not exist it will look for a file with that name. If there is no ending slash, the web server will first look for a file with that name and if it does not exist, it will then look for a directory with that name. In our example, admissions is likely a directory name but could be a file name. Choice B is an incorrect answer. If the domain name is college.edu as stated, college.majors.edu would not be a subdomain of that domain. However, it could be a subdomain of majors.edu if it were a valid domain name. Choice D is an incorrect answer. College.net is a completely different domain name than college.edu. The domain extension .net means "network" and is most commonly used by internet service providers. The domain extension .edu stands for "education" and is most commonly used by colleges and universities.

Consider the following code: a< RANDOM(1,10) If (a>5){ REPEAT a TIMES{ DISPLAY('you win!') } Which line of the code above includes a Boolean expression? a) Line 1 b) Line 2 c) Line 3 d) Line 4

Choice 'B' is the correct answer. A Boolean expression is an expression that evaluates to True or False. Line 2: Has a Boolean condition, (a > 5), which is used to determine which part of the code will be executed.

Which of the following are desired properties of procedural abstraction? Select TWO answers. a) Minimally specified. b) Trivial c) Simple d) Specific

a,c

Which of the following identifies a physical device using the Internet? a) An SMTP b) A domain name c) An IP address d) A packet

An IP address is assigned to every device that can access the Internet, so choice C is correct. Choice B is the address you type in to get a certain site (like www.google.com) Choice A is a protocol for sending and receiving email Choice D refers to a small amount of information that is sent over the Internet

What is the most useful reason for the Domain Name System? a) Domain names make the Internet more organized b) Domain names make the work of search engines like Google possible c) Domain names are easier for humans to remember than the IP addresses of frequently visited websites. d) Domain names must be applicable to their site content.

Choice C is correct. Websites are accessed by their IP addresses, which are 10 digit numbers. It would be impossible to remember and recite the IP address of every website that most Internet users visit in a day! The Domain Name System translates the domain names of websites (like google.com or amazon.com) into the corresponding IP addresses so that human users don't have to worry about too many numbers. Choice A is incorrect; domain names do not necessarily organize the Internet. Choices B and D are also false.

When determining the efficiency of an algorithm you must consider which of the following things? Select TWO answers. a) How long the program takes to run b) The amount of storage the program requires c) How many lines of code the program has d) The platforms on which the program can run

Choices 'A' and 'B' are the correct answers. Efficiency of an algorithm includes both execution time and memory usage.

Which of the following statements about packets is TRUE? a) Packets must be sent in order so they can be reassembled at the end host. b) Packet switching results in a sustained connection between two hosts. c) All packets must pass through a centralized router to be verified before reaching their destination. d) None of these statements are true.

None of the statements are true. Packets can be sent in any order because they contain bits explaining how to reassemble them at their destination choice A. Packets can follow any path that is available to get the destination, so there is no sustained connection between the start host and the end host choice B. There is no centralized router that packets must travel through choice C. Thus, choice D is correct.

Internet users need to be able to transfer private data online, like credit card numbers and social security numbers. Some cryptographic algorithms help ensure this safety. What makes cryptographic algorithms secure? a) The algorithms used for cryptography are based on intractable problems, making them extremely difficult to break. b) The algorithms used for cryptography have been used for such a long time that we know they are very secure. c) The algorithms used for cryptography are solvable, but the solutions are kept under a secure government protection service. d) The algorithms used for cryptography are a secret.

The mathematical foundation of the cryptographic algorithms for symmetric and public keys is based on intractable (or unsolvable) problems. This means that it's very difficult for third parties to figure out how to decode messages not meant for them. This makes choice A correct. Choice B is not correct; there have been many encryption methods that have been proven to be not secure in the past even though they were used for a long time. Choice C is also false. Choice D is not true; we know that the algorithms used for cryptography are based on intractable problems.

Internet users need to be able to transfer private data online, like credit card numbers and social security numbers. Some cryptographic algorithms help ensure this safety. What makes cryptographic algorithms secure? a) The algorithms used for cryptography are based on intractable problems, making them extremely difficult to break. b) The algorithms used for cryptography have been used for such a long time that we know they are very secure. c) The algorithms used for cryptography are solvable, but the solutions are kept under a secure government protection service. d) The algorithms used for cryptography are a secret.

The mathematical foundation of the cryptographic algorithms for symmetric and public keys is based on intractable (or unsolvable) problems. This means that it's very difficult for third parties to figure out how to decode messages that are not meant for them. This makes choice A correct. Choice B is not correct; there have been many encryption methods that have proven to be not secure in the past even though they were used for a long time. Choice C is also false. Choice D is not true; we know that the algorithms used for cryptography are based on intractable problems.

Which of the following strategies to prevent unauthorized access to personal data and accompanying explanation is accurate? Select TWO answers. a) Avoid accessing private data while using public Wi-Fi; it's possible for hackers to intercept packets on a public network. b) Use a firewall; this system does not allow viruses in incoming and outgoing network traffic. c) Delete all emails from unknown addresses; it's impossible to tell when an email contains a virus or phishing scam. d) Use antivirus software; since this software detects and removes many different kinds of viruses.

There are many things that individuals can do to be safe online. Choice A is one of the accurate strategies in this question. Public Wi-Fi networks can be very dangerous because it is easy for anyone to intercept private packets. Choice D is also accurate; antivirus software detects many different kinds of viruses and removes them. Firewalls are great security measures, but choice B is incorrect. Firewalls monitor incoming and outgoing traffic based on rules set by the user. They do not, however, weed out viruses. Choice C is also not accurate; it's not necessary to delete all emails from unknown addresses. A better precaution is to never reply to an email with personal information like social security or credit card numbers. Therefore, the correct answers are choices A and D.

Two students are trying to predict the local results of an upcoming election. The students think of two ways to make their prediction: I. The students assign some numbers on a pair of dice to one candidate and some numbers to the other candidate based on the way their city has voted in the past. They roll the dice to predict who will win the election. II. The students conduct a random survey of local citizens, analyze voting data from the past several years, and study elections in other parts of the country that were very similar to the current one to create a model that will predict the winner of the election. Which of the following statements about options I and II are true? Select TWO. a) Option II is a simulation but Option I is not. b) The level of abstraction is different for each option. c) Option II is a better simulation than Option I. d) The students could choose either option for their simulation depending on their situation.

b, d