The three groups of amphibians: Frogs, Salamanders, Caecilians are different when they reach adulthood. Frogs have four legs with strong hind legs and no tails. Salamanders have tails and four short, weak legs that cause them to walk instead of jump. Lastly, Cacilians have no legs and are burrowing animals.
Amphibians must live in moist environments because they loose water through their thin skin. They need to be near water to replenish the lost water. Also their skin helps them breathe and they can get oxygen from the water.