To be useful, an index fossil is produced by an organism that:
A) is not well preserved.
B) existed for a relatively short time.
C) existed for a very long time.
D) lived in one place only.

Question

Quizplus · Accepted Answer

An index fossil must be produced by an organism that existed for a relatively short time. This is because it can be used to date and correlate rock layers that contain it to other rock layers in different locations. If the organism existed for a long time, it would not be as useful for dating specific rock layers.

To Be Useful, an Index Fossil Is Produced by an Organism