Index fossils help scientists estimate the age of a rock because index fossil species only existed for a relatively short time. What happened to the species that are now used as index fossils?
They became extinct. They changed their diets. They hid in marine sediments. They migrated to new environments.
Question: Index fossils help scientists estimate the age of a rock because index fossil species only existed for a relatively short time. What happened to the species that are now used as index fossils?
A. They became extinct.
B. They changed their diets.
C. They hid in marine sediments.
D. They migrated to new environments.
Answer: