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What are index fossils?

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Index fossils are fossils of organisms that were abundant, widespread, and existed for a relatively short period of geological time. They are used to help date and correlate the age of rock layers.

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Why are trilobites considered good index fossils?

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Trilobites are considered good index fossils because they were abundant, widespread geographically, and lived for a short time period.

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What does the law of crosscutting state?

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The law of crosscutting states that a geological feature (like a fault or intrusion) is younger than any rock layer it cuts through.

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What is relative age?

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Relative age is the age of a rock or fossil in comparison to the ages of other rocks or fossils, rather than an exact age.

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How do sedimentary rocks usually form?

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Sedimentary rocks usually form horizontally through the accumulation and compaction of sediments.

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What is the difference between absolute age and relative age?

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Absolute age is the actual age of a rock or fossil, often determined by radiometric dating, while relative age is its age compared to other rocks or fossils.

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What is an example of a geological feature that can be dated using relative age dating?

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An example of a geological feature that can be dated using relative age dating is a fault, which can be determined to be younger than the rocks it cuts through.

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What is the significance of Fault E and Intrusion D in relative dating?

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In relative dating, if Fault E cuts through Intrusion D, then Fault E is younger than Intrusion D.

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What is the principle of superposition?

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The principle of superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

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How can fossils help in relative dating?

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Fossils can help in relative dating by providing information about the age of the rock layers in which they are found, especially if they are index fossils.