Question

When did abundant fossil evidence first appear in the geologic record?

Answer 1

Answer:

540 million years ago

Explanation:

Cryogenic is a geologic period dominated by glaciers and occurring prior to the Cambrian, when the fossil record shows a so-called explosion of most major groups of complex animals, including all the bilaterians (animals with a left and right side, unlike corals and sponges) — around 530 million years ago.

Answer 2

Three billion years ago, according to National Geographic