Question

why is fossil 4 not a good fossil to use as an index fossil? *outcrop 1outcrop 2outcrop 3outcrop 4(1) (2) (3) (4)it is not widespread.it is not unique.it is not short lived (lived for multiple periods).

Explanation:

Index fossils need to be widespread, short-lived, and distinctive. Looking at the outcrops, fossil 4 appears only in Outcrop 1 and Outcrop 3, meaning it is not found across most of the sampled geographic area. A good index fossil must be geographically widespread to help correlate rock layers across different locations.

Answer:

It is not widespread.