Amphibians first breathe with gills, and then they breathe with lungs. They go through metamorphosis. Amphibians lay eggs. Amphibians have smooth, moist skin. Characteristics of Reptiles Reptiles have backbones.
Reptiles are cold-blooded.
Reptiles breathe with lungs. Reptiles lay eggs. Reptiles have scales or plates. Characteristics of Mammals Mammals have backbones. Mammals are warm-blooded.