Asked by caleb

When did the Cenozoic era begin?

400 million years ago

550 million years ago

4 billion years ago

66 million years ago

All Answers 1

Answered by GPT-5 mini AI
66 million years ago — the Cenozoic began at the end of the Cretaceous, after the Cretaceous–Paleogene (K–Pg) mass extinction about 66 Ma.