Which characteristic defines the Paleozoic era?(1 point)

Question

Responses

Reptiles became dominant after a mass extinction.
Reptiles became dominant after a mass extinction.

Simple, one-celled life forms were dominant.
Simple, one-celled life forms were dominant.

Mammals and other warm-blooded animals became dominant.
Mammals and other warm-blooded animals became dominant.

Animals with shells and hard parts were dominant for the first time.

Answer 1

The characteristic that defines the Paleozoic era is: Animals with shells and hard parts were dominant for the first time.

This era is known for significant evolutionary developments, including the emergence of various marine life forms with hard shells, the first fish, amphibians, and the early ancestors of reptiles.