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.

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

Simple, one-celled life forms were 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 is marked by the development and diversification of many different forms of life, particularly during the Cambrian period when a significant increase in the complexity and diversity of life occurred, including the emergence of hard-shelled organisms.