Question

When did abundant fossil evidence appear in the geologic record?


540 million years ago


100 million years ago


1.0 billion years ago


2.7 billion years agoJ

Answer 1

Abundant fossil evidence first appeared in the geologic record around **540 million years ago** during the Cambrian Explosion, which marks a significant increase in the diversity and complexity of life forms. Prior to this event, fossils were relatively rare and comprised primarily of simple microorganisms.