Which characteristic defines the Paleozoic era?(1 point) Responses Mammals and other warm-blooded animals became dominant. Mammals and other warm-blooded animals became dominant. 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.

1 answer

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 and diversification of many marine life forms, including those with calcified shells, particularly during the Cambrian Explosion.