1. Amphibians Most amphibians such as frogs can live in water and on land. Therefore, they must have respiratory structures that enable them to breathe in water as well as on land. 2. Gas exchange between the air and bloodstream occurs in three locations in a frog (a) the skin (b) the lining of the mouth and (c) the lungs 3. order to ventilate the frog uses its throat to pump air into the lungs. Breathing occurs in four steps: (i) The throat moves down, drawing air into the mouth through the nosrils. (ii) The nostrils close and the throat moves up, forcing air into the lungs. (iii) The throat moves down drawing air back out of the lungs.