Which evidence suggests that several mass extinctions have occurred during earth's history?

fossils provide information about water level and temperature.
many fossils demonstrate that organisms have changed over time.
fossils of the same species have been found on distant continents.
many fossils of organisms that are no longer living have been discovered.

Many fossils of organisms that are no longer living have been discovered.

Explanation:

Mass extinctions could be first identified because of the traces they left in the fossil record. In the strata, the lower, older rock layer shows a diversity of fossil life forms, and the younger lawyer above is depauperate if we compare.  

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