Oce test 4 chap 11

Match the term or phrase with its best descriptor. *standing stock*

available biomass of a target species

What is precession in Earth's orbit?

change in the orientation of Earth's axis

Which of the following could be a direct result of the cycles of eccentricity, obliquity, and precession on Earth?

climate change

Coastal wetlands are characterized by?

high levels of organic matter in the tidal zone and anoxic muds

Climate models and observations to date indicate that the oceans will warm the most in _________.

high-latitude areas

Match the pollutant with its general category. *crude oil*

hydrocarbons

An isothermal temperature profile from surface to seafloor may exist in coastal ocean waters __________.

in either low-latitude waters or high-latitude waters

Of the following locations, where would you expect to find the HIGHEST annual oceanic productivity? Select only one answer.

in middle-latitude waters along a continental margin

Match the term or phrase with its best descriptor. *by-catch*

incidental catch

Natural causes for global climate change include all the following except :

increase in elevation.

If the current trend in the loss of coastal wetlands does not change, what consequence(s) would you predict?

increased loss of marine fisheries

Minamata disease is associated with?

ingestion of methyl mercury-contaminated fish and shellfish

At the mouth of the Amazon River in Brazil, how would the coastal waters be characterized with respect to temperature and salinity?

isothermal with a strong halocline

Under the protection of the Law of the Sea Treaty, a coastal nation has the right to ___________.

extract oil at will within the jurisdiction of their Exclusive Economic Zone (EEZ)

What example of global engineering aims to accelerate the ocean's natural biological pump?

fertilization of ocean water with iron

Recent worldwide sea level rise can be attributed to all of the following except the:

geological uplifting of ocean basins.

The maximum sustainable yield (MSY) is best defined as?

largest catch that can be taken without overfishing.

Productivity in polar oceans is?

light-limited

Match the organism or definition with the correct description of its food preference. *anchovy*

herbivore

Water in the eastern parts of Chesapeake Bay tends to be more saline than water farther west because __________.

ocean water entering the bay hugs the eastern shore because of the Coriolis effect

According to the World Health Organization definition of marine pollutants, __________ is NOT a pollutant.

oil from offshore seeps

Match the organism or definition with the correct description of its food preference. *an organism that feeds on plants or animals*

omnivore

Amphipods are _________.

deposit feeders

Of the following statements about the greenhouse effect and global warming, which is/are true? -The greenhouse effect began about 200 years ago as a result of human-related activities. -Global warming will likely result in more prolonged droughts. -Global warming will likely cause the oceans to boil away on Earth. -Global warming will likely result in more rainfall. -Global warming will likely result in a rise in sea level due to melting glaciers and thermal expansion of warm ocean waters. -Global warming will likely result in more intense tropical storms.

-Global warming will likely result in more prolonged droughts. -Global warming will likely result in more rainfall. -Global warming will likely result in a rise in sea level due to melting glaciers and thermal expansion of warm ocean waters. -Global warming will likely result in more intense tropical storms.

Of the following statements about the physical characteristics of coastal oceans, which is/are true? -Because of onshore wind and coastal runoff, geostrophic currents along western North America flow northward. -In high-latitude areas, the coastal ocean is isothermal (has a uniformly low temperature from surface to deeper waters). -Most coastal waters have very high salinity due to freshwater runoff. -In low-latitude areas where there is no mixing, surface water temperatures can be very high. -In middle-latitude coastal oceans where evaporation is high, a halocline can develop.

-Because of onshore wind and coastal runoff, geostrophic currents along western North America flow northward. -In high-latitude areas, the coastal ocean is isothermal (has a uniformly low temperature from surface to deeper waters). -In low-latitude areas where there is no mixing, surface water temperatures can be very high. -In middle-latitude coastal oceans where evaporation is high, a halocline can develop.

Of the following statements about the characteristics of coastal waters, which is/are true? -Coastal waters typically have high biologic productivities. -Coastal waters are more affected than the open ocean by river runoff and tidal currents. -A very large percentage of the oceans' biomass is located in coastal waters. -Coastal waters have high biologic diversity. -Coastal waters are rarely altered by human activities.

-Coastal waters typically have high biologic productivities. -Coastal waters are more affected than the open ocean by river runoff and tidal currents. -A very large percentage of the oceans' biomass is located in coastal waters. -Coastal waters have high biologic diversity.

Which of the following characteristics of Earth's relationship to the Sun explains the existence of Earth's seasons? Choose all that apply. -Earth has a satellite called the Moon, which rotates around Earth. -Earth orbits around the Sun, completing one orbit each year. -Earth's axis is tilted relative to its orbital plane. -Earth spins on its axis, completing one rotation each day. -Earth's axis always points in the same direction relative to the stars.

-Earth orbits around the Sun, completing one orbit each year. -Earth's axis is tilted relative to its orbital plane. -Earth spins on its axis, completing one rotation each day. -Earth's axis always points in the same direction relative to the stars.

Of the following statements about marine fisheries, which is/are true? -Most marine fish stocks are currently being fished at their maximum sustainable yield. -Fishing practices have removed 90% of large marine predatory fish species. -A recent study indicates that if fishing practices continue, marine fish stocks will be depleted by 2048. -The world's total marine fish catch continues to increase year after year. -The marine fishing industry has developed new high-tech methods that have virtually eliminated bycatch. -In U.S. waters, 80% of commercial marine fish stocks are fully exploited or overfished.

-Fishing practices have removed 90% of large marine predatory fish species. -A recent study indicates that if fishing practices continue, marine fish stocks will be depleted by 2048. -In U.S. waters, 80% of commercial marine fish stocks are fully exploited or overfished.

All of the following are examples of pollutants in the marine environment except: -sewage sludge. -heavy metals such as mercury and silver. -phytoplankton. -hydrocarbons. -nutrient inputs such as nitrogen and phosphorus compounds.

-phytoplankton

Of the following statements about oceanic productivity, which is/are true? -In middle-latitude oceans, the fall bloom is limited by the lack of sunlight. -In middle-latitude oceans, the fall bloom is limited by the lack of nutrients. -In middle-latitude oceans, the spring bloom is limited by the lack of sunlight. -In tropical oceans, productivity is limited year-round by the lack of sunlight. -In middle-latitude oceans, the spring bloom is limited by the lack of nutrients. -In tropical oceans, productivity is limited year-round by the lack of nutrients.

-In middle-latitude oceans, the fall bloom is limited by the lack of sunlight. -In middle-latitude oceans, the spring bloom is limited by the lack of nutrients. -In tropical oceans, productivity is limited year-round by the lack of nutrients.

Of the following statements about oceanic productivity in polar regions, which is/are true? -In polar oceans, there is incredibly high productivity in the summertime. -In polar oceans, productivity is limited by the lack of sunlight in the winter. -In polar oceans, nutrient concentrations are usually adequate and do NOT limit productivity. -Polar oceans typically display a strong, permanent thermocline. -In polar oceans, productivity is high year-round.

-In polar oceans, there is incredibly high productivity in the summertime. -In polar oceans, productivity is limited by the lack of sunlight in the winter. -In polar oceans, nutrient concentrations are usually adequate and do NOT limit productivity.

Of the following statements about coastal wetlands, which is/are true? -Mangrove swamps are a type of coastal wetland that can protect shorelines from erosion. -Coastal wetlands are good at cleansing polluted water of agricultural runoff, toxins, and other pollutants. -Coastal wetlands often serve as important nursery areas for many species of fish. -Scientists estimate that globally, 50% of all coastal wetlands have disappeared in the past century. -Salt marshes are a type of coastal wetland found only in the tropics.

-Mangrove swamps are a type of coastal wetland that can protect shorelines from erosion. -Coastal wetlands are good at cleansing polluted water of agricultural runoff, toxins, and other pollutants. -Coastal wetlands often serve as important nursery areas for many species of fish. -Scientists estimate that globally, 50% of all coastal wetlands have disappeared in the past century.

Of the following statements, which is/are included in the World Hearth Organization's definition of marine pollution? -Marine pollution results or is likely to result in harmful effects to marine life. -Marine pollution can be a substance or a form of energy. -Marine pollution is harmful to human health only. -Marine pollution is human-made. -Marine pollution is esthetically displeasing (an eyesore). -Marine pollution can be a natural occurrence.

-Marine pollution results or is likely to result in harmful effects to marine life. -Marine pollution can be a substance or a form of energy. -Marine pollution is human-made.

Of the following statements about the iron hypothesis, which is/are true? -Phytoplankton were killed when iron was added to the ocean. -Oceanographer John Martin proposed fertilizing the ocean with iron to increase its productivity. -Adding iron to the ocean removes carbon dioxide from the atmosphere, which helps reduce global warming. -Adding iron to the ocean might cause an ecological disaster in the ocean. -Adding iron to the ocean increased phytoplankton productivity up to 30 times.

-Oceanographer John Martin proposed fertilizing the ocean with iron to increase its productivity. -Adding iron to the ocean removes carbon dioxide from the atmosphere, which helps reduce global warming. -Adding iron to the ocean might cause an ecological disaster in the ocean. -Adding iron to the ocean increased phytoplankton productivity up to 30 times.

Of the following nutrients, which is/are used in photosynthetic primary productivity by phytoplankton? -Boron -Phosphates -Silica -Calcium -Iron Nitrates

-Phosphates -Silica -Nitrates

Of the following natural factors, which have caused past climate changes on Earth? -the amount of marine life in the oceans -changes in solar energy -volcanic eruptions -variations in Earth's orbit -the movement of Earth's tectonic plates

-changes in solar energy -volcanic eruptions -variations in Earth's orbit -the movement of Earth's tectonic plates

Of the following, which are useful as proxy data for understanding past climate changes? -fossil pollen -predictions of when the next large volcanic eruptions could occur -historical documents -annual layers of snow packed in glacial ice -tree-growth rings -sea floor sediments

-fossil pollen -historical documents -annual layers of snow packed in glacial ice -tree-growth rings -sea floor sediments

Of the following, which ocean changes are predicted to result from global warming? -migration of marine organisms into deeper waters and toward the poles -increased transmission distance of sound in the sea -less acidic oceans -lower amounts of dissolved oxygen in seawater -increase in ocean stratification and the development of a stronger thermocline

-migration of marine organisms into deeper waters and toward the poles -increased transmission distance of sound in the sea -lower amounts of dissolved oxygen in seawater -increase in ocean stratification and the development of a stronger thermocline

The percentage of euphotic zone biomass that reaches the deep ocean floor is approximately?

1%

The efficiency of trophic transfers in ecosystems is on average around?

10%

How long is the most important eccentricity cycle for Earth's orbit?

100,000 years

The average rate of primary production in the open ocean is 125 gC/m2/yr. In the most productive ecosystems such as algal beds and coral reefs, the average production is 2000 gC/m2/yr. How many years would it take to accumulate 2000 gC/m2 on the deep-sea floor in the open ocean?

1600 years

How long is the cycle of precession for Earth's orbit?

26,000 years

How much of the Sun's incoming radiation is scattered or reflected back to space before any heating effect is felt on Earth?

31%

Since 1750, the amount of carbon dioxide in our atmosphere has increased by more than?

40%

How long is the cycle of obliquity for Earth's orbit?

41,000 years

How much of the Sun's incoming radiation is absorbed by Earth's surface?

45%

Of the following statements about the Mediterranean Sea, which is/are true? -The Mediterranean Sea is one of the few inland seas in the world that is underlain by oceanic crust. -The warm, salty, and dense Mediterranean Intermediate Water flows out as a subsurface flow over the Gibraltar Sill and into the Atlantic Ocean. -Evaporation in the arid eastern part of the Mediterranean Sea causes an inward surface flow at the Strait of Gibraltar. -The Mediterranean Sea is actually a number of smaller seas connected by narrow necks of water into one larger sea. -Thick salt deposits on the floor of the Mediterranean Sea suggest that it completely dried up about 6 million years ago.

All

Reasons for the loss of coastal wetlands include all of the following except: -industrial development. -coastal housing. -removal of mangroves and other coastal vegetation -agriculture. -all of the above.

All of the above

Which of the following characterizes the pesticide DDT and industrial chemicals such as PCBs? -relatively high toxicity -persistence in the environment -propensity to accumulate in food chains -biologically active -All of the above are correct.

All of the above are correct.

All the following are challenges to managing fisheries except? -incident catch or bycatch. -regulations on the number of fishing vessels. -overfishing. -multinational boundaries. -All the above are correct.

All the above are correct.

Hazards associated with sea level rise include all the following except : permanent inland flooding. drowning of beaches. accelerated coastal erosion. increasing damage from storms. All the above are correct.

All the above are correct.

Although primary productivity in tropical areas is generally low, which of the following tropical locations have unusually high primary productivity rates? Check all that apply. coastal upwelling zones coral reefs All the above tropical areas have relatively high primary productivity. equatorial upwelling zones

All the above tropical areas have relatively high primary productivity.

What would happen to Earth's atmospheric temperature if the amount of incoming shortwave radiation from the Sun decreased and was less than the longwave radiation lost to space?

Atmospheric temperature would decrease.

What would happen to Earth's atmospheric temperature if the amount of shortwave radiation reflected at Earth's surface increased significantly?

Atmospheric temperature would decrease.

What would happen to Earth's atmospheric temperature if the amount of outgoing longwave radiation decreased so that it was less than incoming shortwave radiation from the Sun?

Atmospheric temperature would increase.

What would happen to Earth's atmospheric temperature if the amount of shortwave radiation reflected by clouds decreased significantly?

Atmospheric temperature would increase.

What would happen to Earth's atmospheric temperature if the amount of incoming shortwave radiation from the Sun was the same as the longwave radiation lost to space?

Atmospheric temperature would remain the same.

What is the primary cause of the nearly 20 percent increase in atmospheric carbon dioxide levels since the 1960s?

Burning of fossil fuels

Of the following types of organisms, which are examples of microscopic algae? Krill photosynthetic bacteria Dinoflagellates Diatoms Coccolithophores

Dinoflagellates Diatoms Coccolithophores

Mangrove swamps are protective buffer areas in coastal ecosystems outside of the tropics.

False

t/f An overabundance of oxygen results in eutrophication.

False

t/f Compensation depth is the depth in the ocean where the photosynthetic rate exceeds the rate of cellular respiration.

False

t/f Elevated levels of carbon dioxide in the atmosphere, with subsequent absorption by the oceans, have caused an increase in ocean pH.

False

t/f Greenhouse gases are compounds in the Earth's atmosphere that dissipate heat.

False

t/f If the total caloric content of the autotrophic organisms in a marine ecosystem were 250,000 kilocalories (kcal), then the expected caloric value for the trophic-level consumers at the second level would be 2,500 kcal.

False

t/f Primary productivity is equal to the amount of photosynthesis plus the amount of respiration.

False

t/f Sea surface temperatures have remained unchanged during the past 50 years.

False

t/f The Mediterranean Sea water has little impact on the waters of the Atlantic Ocean.

False

t/f The primary treatment of sewage involves the removal of inorganic nutrients from the liquid effluent.

False

t/f The products of photosynthesis are carbon dioxide (CO2) and water (H2O).

False

t/f The standing stock of a population is the maximum number or biomass of individuals that can be removed sustainably.

False

t/f Worldwide retreat of mountain glaciers has not been documented to date.

False

An international agreement to voluntarily limit greenhouse gas emissions is called the?

Kyoto Protocol.

When are the Sun's rays perpendicular to Earth's surface at the equator? Choose all that apply. June Solstice March Equinox September Equinox December Solstice

March Equinox September Equinox

When less saline water enters a marginal sea above a return flow of saltier water, the circulation pattern is called?

Mediterranean circulation.

Periodic variations in Earth's orbit that can cause natural climate changes are called _________.

Milankovitch cycles

The area of the ocean that produces the largest standing stock of commercial fish is in the?

Nontropical shelf areas

How do the oceans contribute to maintaining a climate that is habitable for humans?

Oceans absorb large quantities of carbon dioxide from the atmosphere.

What impact will increased carbon dioxide absorption by the oceans have on coral reefs?

Reefs will degrade over time, ultimately resulting in large-scale mortality.

The most abundant marine macroscopic algae are members of the Division?

Rhodophyta.

When do all locations on Earth experience equal lengths of day and night? Choose all that apply. September Equinox June Solstice December Solstice March Equinox

September Equinox March Equinox

Match the pollutant with its general category. *concentrated organic matter*

Sewage Sludge

The following are all examples of nonpoint source pollutants in the ocean EXCEPT __________. -nurdles -pesticides -road oil -fertilizer -sewage sludge

Sewage Sludge

How does the inclination of Earth's axis change over the course of a year?

The inclination of Earth's axis does not change.

How will increases in atmospheric carbon dioxide levels affect oceans?

The oceans will become more acidic.

What would happen to the oxygen atoms in ozone if the ozone layer were completely destroyed by ultraviolet radiation?

The oxygen atoms would be bound together in pairs

t/f Bacteria that manufacture carbohydrates in the absence of solar energy are autotrophs.

True

Why are scientists doing research in an underwater lab in the Great Barrier Reef?

To replicate future carbon dioxide levels and measure the changes in coral reef productivity, mortality and health

t/f Carbon dioxide (CO2) has the greatest relative contribution to increasing the greenhouse effect compared to other anthropogenically produced greenhouse gases.

True

t/f Changes in Earth's orbit can impact climate by increasing or decreasing solar input.

True

t/f Dissolved carbon dioxide and pH in the oceans are inversely related.

True

t/f Earth's average surface temperature has increased 0.6°C over the past 30 years.

True

t/f Marine algae that grow close to the limits of light penetration have accessory photosynthetic pigments that absorb high energy, short-wavelength light in the blue region of the electromagnetic spectrum.

True

t/f Pollutants are any substance that has a negative effect on the environment.

True

t/f Primary producers, herbivores and carnivores are all examples of trophic levels within a food chain or food web.

True

t/f Studying carbon dioxide trapped in glacial ice can be used to determine Earth's ancient climate.

True

t/f The Earth's climate system involves the exchange of heat and water among the atmosphere, hydrosphere, geosphere, biosphere, and cryosphere.

True

t/f The amounts of carbon dioxide and available nutrients affect the rate of primary production in an ecosystem.

True

t/f The distinction between a food chain and a food web is that a food chain describes a linear relationship among trophic levels whereas a food web describes the interconnected relationships among trophic structures in nature.

True

t/f The fourth IPCC report on international climate change (2007) confirmed that human activity has produced climate change beginning in the mid-20th century.

True

t/f The greatest sources of hydrocarbons in the marine environment include urban runoff and petroleum shipping.

True

t/f The group of marine macroscopic algae with the highest abundance and greatest geographic distribution belong to the Division Rhodophyta.

True

How is ozone formed in the stratosphere?

Ultraviolet radiation breaks apart molecules made up of paired oxygen atoms. Individual oxygen atoms bond with paired oxygen molecules to form ozone.

How does ultraviolet radiation cause ozone depletion?

Ultraviolet radiation breaks down CFC, a molecule containing chlorine. Chlorine then breaks one oxygen atom away from ozone, leaving behind a paired oxygen molecule.

Marine seed-bearing plants include all the following except : Ulva. mangroves. surf grass. eelgrass. Spartina alterniflora.

Ulva

What is ozone?

a molecule made up of three oxygen atoms

Of the following statements about feeding strategies, which is/are true? -Suspension feeding involves filtering plankton from seawater. -Deposit feeders include worms that ingest sediment that is coated with organic matter. -Carnivorous feeding involves either passive or active predation. -Suspension feeding is the same thing as filter feeding. -Carnivorous feeding involves organisms directly capturing and eating other animals.

all

Of the following, which are examples of climate feedback loops? heat uptake by the oceans the role of clouds at different altitudes the addition of water vapor into the atmosphere the shading effect from air pollution the presence of fine atmospheric particles called aerosols

all

The scientific consensus is that global warming has led to __________.

an increase in oxygen-depleted dead zones

Where does the length of day remain the same throughout the year?

at the equator

Match the organism or definition with the correct description of its food preference. *diatom*

autotroph

Lagoons that form behind barrier islands are examples of?

bar-built estuaries.

Combustion of fossil fuels results in a transfer of carbon from the __________.

biosphere to the atmosphere

The gas(es) that has/have the greatest relative contribution to increasing the greenhouse effect is/are?

carbon dioxide (CO2).

Match the organism or definition with the correct description of its food preference. *dolphin*

carnivore

Match the organism or definition with the correct description of its food preference. *sand star (Astropecten)*

carnivore

Of the following locations, which is/are exceptions to the general rule that productivity is steady and low in tropical regions? coastal upwelling coral reefs equatorial upwelling in the deep ocean, far from land anywhere there is a strong thermocline

coastal upwelling coral reefs equatorial upwelling

The depth at which the cellular respiration rate equals the photosynthetic rate is referred to as the?

compensation depth for photosynthesis

Match the organism with its correct descriptor of energy use or trophic level. *flounder*

consumer

Nutrient flow in an ecosystem is?

cyclical.

mportant marine autotrophs that have silica incorporated into their cell walls are?

diatoms.

Match the term or phrase with its best descriptor. *Marine Mammal Protection Act*

dolphins and other mammal protection

In the ongoing processes of photosynthesis, respiration, and decomposition in the ocean, all components are recycled except _________.

energy

How much of the Sun's ultraviolet radiation reaches Earth's surface?

little of the ultraviolet radiation

With the depletion of fish stocks in coastal waters, more fishing is being conducted in deeper waters. Deep-water species are becoming endangered at a rapid rate, primarily because _________.

most deep-water organisms have lower metabolic rates; therefore, they grow, mature, and reproduce at a slower rate

An increase in cloud cover and a corresponding decrease in absorption of solar radiation is an example of a?

negative-feedback loop.

An increase in cloud cover due to higher moisture content in the atmosphere is an example of a?

negative-feedback loop.

The two most significant human sources of oil pollution in the marine environment are?

normal oil tanker/shipping operations and urban run-off.

In dead zones resulting from eutrophication, animal life is absent due to the lack of _________.

oxygen

What is another name for the ozone layer?

ozonosphere

Match the pollutant with its general category. *DDT*

persistent organic pollutants

Match the pollutant with its general category. *PCBs*

persistent organic pollutants

The greatest amount of oil pollution in the ocean from human sources is from __________.

petroleum consumption

Of the following types of organisms, which one is considered to be LOWEST in a marine food web? Select only one answer.

photosynthetic bacteria

In general, the rate at which energy is stored by organisms through the formation of organic matter is called?

primary productivity.

Match the organism with its correct descriptor of energy use or trophic level. *Sargassum*

producer

The international Law of the Sea treaty __________.

provides for arbitration of disputes

Mass mortality events of marine mammals and birds may occur after ingesting prey items that contain algal toxins. What organism that can cause harmful algal blooms should humans be concerned about if animals in the area are having seizures and exhibiting erratic, "drunken-like" behavior?

pseudo-nitzschia, because it causes amnesic shellfish poisoning.

Concerned individuals can reduce their personal contribution to greenhouse gas emissions by doing all the following except :

reducing the area covered by pavement or structures (houses, garages, pools, decks, etc.) in urban and suburban areas.

Only some shortwave radiation from the Sun reaches Earth's surface. What is the leading cause of this radiation loss?

reflection by clouds

Burning of fossil fuels is chemically similar to?

respiration

Catches above the maximum sustainable yield result in?

result in overfishing.

Estuarine circulation associated with a deep, high river volume system where no horizontal salinity gradient exists at the surface is called a?

salt wedge estuary.

The oceans' "biological pump" _________.

takes carbon from the photic zone and stores it in deep ocean water and seafloor sediments

An estuary produced by faulting or folding of rocks that creates a dropped-down section into which a river flows is called a?

tectonic estuary.

The relative productivity in the world's oceans from most productive to least productive is?

temperate waters, polar waters, tropical waters.

The warming of Earth's surface and atmosphere is a natural process controlled by the greenhouse effect. It is also being altered by human emissions, a phenomenon that is often referred to as ___________. the albedo effect the ozone hole the anthropogenic greenhouse load the enhanced greenhouse effect thermohaline circulation

the anthropogenic greenhouse load the enhanced greenhouse effect

What is obliquity in Earth's orbit?

the inclination of Earth's axis

What is eccentricity in Earth's orbit?

the shape of Earth's orbit

What is the December solstice?

the time of the year when Earth's geographic North Pole is leaning most directly away from the Sun

What is the June solstice?

the time of the year when Earth's geographic North Pole is leaning most directly toward the Sun

If primary photosynthetic productivity in a given area of the ocean is 300 gC/m2/yr, about how much organic matter is added to the seafloor sediments per square meter each year?

three grams

How is energy transferred from Earth's surface to Earth's atmosphere? Choose all that apply. through conduction through absorption through the greenhouse effect through convection through latent heat in water vapor

through conduction through the greenhouse effect through convection through latent heat in water vapor

Biomagnification of toxic substances means that __________.

toxic substances become increasingly concentrated in the tissues of organisms in each higher level of the food web

What natural cause of climate change is most similar to the major anthropogenic source?

volcanic eruptions

A fact regarding photosynthesis is that _________.

water and carbon dioxide are converted to oxygen gas and sugar

Of the following atmospheric gases, only _________ is an important greenhouse gas.

water vapor (H2O)