Decide which structure is used in the following sentences.
Frogs belong to the amphibian family. They have vertebra and their skin is smooth and shiny. In addition, they are cold-blooded and breathe through their skin. All of these traits make them amphibious.
Frogs belong to the amphibian family. They have vertebra and their skin is smooth and shiny. In addition, they are cold-blooded and breathe through their skin. All of these traits make them amphibious.