Answer to Question 1
Answer: Reptiles are cold-blooded and lay eggs to bear young whereas mammals are warm-blooded and bear live young that they tend by suckling. The warm-blooded mammals were able to survive in more diverse habitats than reptiles because they didn't have to rely on external sources to generate energy to move and function.
Answer to Question 2
Answer: The first land animals were lobe-finned fish, which made their way onto land during the Devonian Period. These fish possessed internal sacks that could be filled with air to supplement their respiration through gills. They would also have had fins that were strong enough to move overland.
The sites of early embryonic development in mammals.
The deer mouse and the African elephant represent extremes among mammals of r versus K selection.
Darters such as this male greenside darter form a diverse and distinctive subfamily of fishes within
The thorax of apes, including humans, is broad but shallow in contrast to the narrower, deeper chest
Mammoths – Larger Cenozoic Mammals
Cenozoic Era: Age of Mammals