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 fossils of organisms that existed for a short, well - defined geological time period and were widespread. Scientists use them to correlate (compare) rock layers from different, distant locations. If the same index fossil is found in rock layers at two far - apart places, it suggests those rock layers were formed during the same time period.

• Option 1: Studying the ranges of different organisms is not the main use of index fossils.
• Option 2: Index fossils don't directly help in understanding the origin of life.
• Option 3: This matches the main function of index fossils (correlating rock layers across distances).
• Option 4: Index fossils are not used to understand the rock type when the organism lived.

Answer:

C. They aid in comparison of rock layers at distant locations.