Answer:
Paleozoic era
Explanation:
The first major extinction in Earth's history occurred two to five million years ago, two deadly climaxes over hundreds of thousands of years. Most creatures lived in the seas at this time, so many of the marine creatures of that time, such as trilobites, brachiopods, and graptolites, were destroyed. During this third deadliest extinction, 5 to 5 percent of all species have been extinct.
