Most Modern Phyla of Animals Appear as Fossils at the Beginning

Question

Most modern phyla of animals appear as fossils at the beginning of the:
A) Permian.
B) Cambrian.
C) Devonian.
D) Cretaceous.

Accepted Answer

The Cambrian Explosion, which occurred approximately 541 million years ago, marks the period when most major groups of animals first appear in the fossil record. This event is seen as the rapid diversification of multicellular organisms.