What do amphibians reptiles and mammals all have in common?

Mammals have few similarities to amphibians as compared to the number of differences between them. However, some similarities include:

1. Both, as adults, breathe oxygen.

2. Both have spines and endoskeletons.

3. Both have bilateral symmetry.

4. Both have many internal organs in common, such as bones, muscles, brains, hearts, lungs, kidneys, bladders*, livers, tracheae, gall bladders, esophagi, stomachs, and intestines.

5. Both are tetrapods, but some species of both classes (e g whales, caecilians) have lost some of their limbs.

*The bladders of amphibians are usually not connected to the urinary ducts. They are in a pocket in the cloaca.