The frogs belong to the order of amphibians. These are vertebrates, tetrapods (four-legged), oviparous (they lay eggs).
The early life of a frog is aquatic. The eggs hatch in fresh water and the larvae, called tadpoles, are more like a fish than a frog. The tadpole is fully adapted to aquatic life. It breathes through gills and moves with a fin. It is herbivorous in the first few weeks.
During its growth, the tadpole turns into a frog, a carnivorous land animal, moving with 4 legs and breathing with lungs.