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.

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

Mammals and other warm-blooded animals became dominant.

Answer 1

The characteristic that defines the Paleozoic era is:

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

This era saw the emergence of a diverse range of life forms, including the Cambrian explosion where many organisms with hard shells first appeared.