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.

Explanation:

Index fossils are used to identify and date the layers of rock in which they are found. If an index fossil is found at location 1 but not at location 2 (which is of the same relative age), it is most likely that the organism did not exist at location 2. The other options are incorrect:

• If the layer at location 2 was too old (option 1), it would not be of the same relative age as location 1.
• Locations being close together (option 2) does not prevent an index fossil from being present if the organism existed there.
• If the layers at location 2 formed much earlier (option 4), they would not be of the same relative age as location 1.

Answer:

The organism did not exist at location 2.