Unit Test

For which object would a geologist use carbon-14 dating to determine age?

The bones of animals

According to the principle of original horizontality, what most likely happened to the rock layers in the background?

They were deposited horizontally and then shifted by a geologic event.

How might an entire insect be preserved?

Tree sap flows over the insect and hardens.

Which best explains a primary reason for the inability of life to exist in Earth's early atmosphere?

Volcanic eruptions and comet collisions added different gases to the atmosphere.

Which information can be determined using half-life?

age of material

What are the three elements that geologists measure to determine the age of an organism's remains?

carbon-14, nitrogen, and carbon-12

Which is one piece of information that fossils in samples from Earth's crust reveal about Earth's history?

changes in climate

Which feature causes a gap in the geologic record?

erosion

Which phrase describes the relative age of a rock?

uses the law of superposition to determine which rock is older or younger

Which best describes eras and periods?

Eras and periods both appear at the start of the Cambrian period.

Which statement describes the geologic features?

Fault Q occurred before layer K was deposited.

Which evidence suggests that several mass extinctions have occurred during Earth's history?

Many fossils of organisms that are no longer living have been discovered.

Which is the first step in the process during the formation of molded fossils?

Organisms are buried under sediment.

Which method is most likely used to identify what happened before the start of the Paleozoic era?

Scientists examine fossil evidence during the Precambrian time.

After two half-lives, how much of the original material has decayed?

75 percent