Amphibians have a relatively complex circulatory system with a three-chambered heart.
All frogs are amphibians.
Frogs have a relatively complex circulatory system with a three-chambered heart.
What has a relatively complex circulatory system with a three-chambered heart?
1) sharks
2) pan
3) frogs
4) Man
5) Birds
6) alpacas
7) salmon
8) a fish