Question

Which event is most likely if an index fossil is found in a layer at location 1, but the layer and index fossil are not found at location 2 nearby, which is known to be the same relative age?

The layer at location 2 is too old to contain fossils.
The locations were too close together.
The organism did not exist at location 2.
The layers at location 2 formed much earlier than those at location 1.

Answer 1

The organism did not exist at location 2.

Index fossils mark a time interval, but a species may have had a limited geographic or environmental range (or simply wasn't preserved there), so a time-equivalent layer nearby might lack that fossil.