Question

Which is a difference between the Paleozoic and Mesozoic era?

Animals lived in the water during the Mesozoic and on land in the Paleozoic.
The first birds emerged in the Paleozoic era while mammals first emerged in the Mesozoic.
Many different species of dinosaurs lived in the Mesozoic, but they all died off in the Paleozoic.
Animal complexity increased during the Paleozoic while the first flowering plants appeared in the Mesozoic era.

Answer 1

The fourth option is correct.

Explanation: Animal complexity rose dramatically during the Paleozoic (e.g., the Cambrian explosion). Flowering plants (angiosperms) first appeared later, in the Mesozoic (especially the Cretaceous). The other choices are incorrect — dinosaurs lived in the Mesozoic (not the Paleozoic), birds appeared in the Mesozoic (not the Paleozoic), and both eras had marine and terrestrial animals.