Question

2 Points

What is an index fossil?
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A. A fossil that contains rocks and minerals
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B. A fossil found in rocks from one time period
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C. A fossil that has vestigial structures
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D. A fossil that formed 300 million years ago​

Answer 1

B, A fossil found in rocks from one time period

Step-by-step explanation:

Fossils are used to determine the ages of rock layers. Index fossils are the most useful for this. Index fossils are of organisms that lived over a wide area. They lived for a fairly short period of time. An index fossil allows a scientist to determine the age of the rock it is in. Hope that this helps you :)