What best describes index fossils? Organisms that existed over a limited period Organisms whose age is hard to detect Fossils that are used in radioactive dating Fossils of the most ancient organisms

i think its fossils that are sued in radioactive dating because index fossils are fossils that are useful for dating and correlating the strata in which it is found, and radioactive dating is the only option that has to do with finding time.

Explanation

i'm not sure at all please do a little more research before putting my answer down

double the distance = divide strength by 4

wavelegth as in spectrum red oygbiv