Question

location a <--- 200 miles apart ---> location b
what is the absolute age of fossils found in layer 4?
it is older than layer 2
it is the oldest rock layer in this picture
400 million years
200 million years

Explanation:

Step1: Identify age - related information

From the diagram, the dashed line connecting the layers shows the age. The layer corresponding to layer 4 has a dashed - line labeled 400 million years ago.

Answer:

400 million years