You are presented with the quiz "How do ost frogs breathe as tadpoles?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "most amphibians breathe with gills as larvae and with lungs as adults" and "frogs are the most durable of the amphibians". So, what's the best answer to the question?

(a). gills;
(b). sucking in air;
(c). oxygen;
(d). lungs;
(e). ligt;
(f). nektar;
(g). skin;
(h). ovaries;
The answer is:
(a).