Which characteristic defines the Paleozoic era?(1 point)

Question

Responses

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

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

Reptiles became dominant after a mass extinction.

Answer 1

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