Geologic Time Scale and Fossils

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What is an index fossil?

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A fossil that is used to establish the age of a rock layer because it is distinct, abundant, and widespread, and the species that formed it existed for only a short span of geologic time.

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What type of fossil is a bug stuck in amber?

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Preserved remains.

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What are fossil fuels?

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Energy-rich substances formed from the remains of organisms, including coal, oil, and natural gas.

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What does the principle of uniformitarianism state?

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Earth's processes occurring today are similar to those that occurred in the past.

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What are fossils?

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Preserved remains of plants and animals from the remote past.

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What is the fossil record?

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The history of life on Earth as documented by fossils.

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What is a mold fossil?

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A fossil that forms when an organism leaves an impression in sediment.

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What is a cast fossil?

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A fossil that forms when a mold is filled with minerals or other materials.

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What are trace fossils?

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Fossils that provide evidence of the activities of ancient organisms, such as footprints or burrows.

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What is relative age?

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The age of a rock or fossil in comparison to other rocks or fossils.