What does a mass extinction look like in the fossil record? O A. A layer of rock contains only fossils of living things that no longer
exist on Earth.
B. A layer of rock contains only fossils of species that presently exist
on Earth.
O C. A younger layer of rock contains a much greater variety of fossils
than a slightly older layer of rock does.
D. An older layer of rock contains a much greater variety of fossils
than a slightly younger layer of rock does.