Question

Index fossils are fossils of organisms that ____.

Answer 1

Answer:

They were spread over a wide area, and lived over a short period of time

Explanation:

Index fossils are fossils that are used to date back geologically.

Answer 2

Answer: Option (1)

Explanation: Index fossils are those fossils which were present only for a short period of time and had wide geographical distribution. This fossils plays an important role in the correlation of rocks i.e two same rocks appearing at two different places, as well as, it helps in the determination of the age of rock. For example, ammonites.

Thus, the correct answer is option (1).