Yes they did, but birds are much more related to dinosaurs than mammals are. All life forms evolved from Unicellular organisms.
And why, do you think, did it take biologists until XIX century to agree upon the unicellular part?
Yes they did, but birds are much more related to dinosaurs than mammals are. All life forms evolved from Unicellular organisms.
And why, do you think, did it take biologists until XIX century to agree upon the unicellular part?