Question

20. The five recognized periods of mass extinction have- *

Answer 1

1. Ordovician Mass Extinction (about 44o million years ago)

2. Devonian Mass Extinction (about 375 million years ago)

3. Permian Mass Extinction (about 250 million years ago)

4. Triassic-Jurassic Mass Extinction (about 200 million years ago)

5. Cretaceous-Tertiary Mass Extinction (about 65 million years ago)

Step-by-step explanation: