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 relatively short geological time span but were widespread. Their main use is to correlate (compare) rock layers from different, distant locations. Let's analyze each option:

• Option 1: Studying ranges of organisms is not the primary use of index fossils.
• Option 2: Index fossils don't focus on the origin of life.
• Option 3: Correct, as index fossils help match rock layers across different areas by indicating the same time period.
• Option 4: They don't advance understanding of rock type at the organism's time; their role is about time correlation for rock layers.

Answer:

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