Amphibians have a relatively complex circulatory system with a three-chambered heart.
All frogs are amphibians.
Frogs have a three-chambered heart.
Frogs have a _-chambered heart.
Options:
[a] alveoli
[b] organ
[c] ovaries
[d] oxygen
[e] edible
[f] three
[g] nektar
[h] CO 2