Question

how do index fossils help scientists? they aid in the study of ranges of different organisms. they advance understanding of the origin of life on earth. they aid in comparison of rock layers at distant locations. they advance understanding of rock type at the time the organism lived.

Explanation:

Index fossils are widespread and existed for a short - time period. They help geologists match rock layers in different locations as they can be used as time - markers.

Answer:

They aid in comparison of rock layers at distant locations.