Question

What major animal group replaced dinosaurs and reptiles in the cenozoic era?

Answer 1

mammals is the answer :)

have a great day

Answer 2

 the kt event set the stage for the Cenozoic era that began 65 million years ago however as the dinosaurs perished at the end of the cretaceous the mammals took the center stage. even as mammals increased in numbers and diversity, so did the birds, reptiles, fish, insects, trees, grasses, and other forms of life.