What major animal group replaced dinosaurs and reptiles in the Cenozoic era? lobe-finned fishes amphibians mammals birds

mammals and birds

Explanation:

The animals that replaced the dinosaurs and the reptiles were the mammals in the Cenozoic era which includes the bats, the whales, and hoofed animals, carnivores, along with rodents, and the primates. And they recolonized the land, ocean and the air and only some parts of the dinosaurs that are found today are found in traces of the modern birds like the ostrich etc.

mammals because that is a fact