Given the question: Amphibians have a relatively complex circulatory system with a three-chambered heart, and frogs have a three-chambered heart, consisting of two atria and a single ventricle. Given these facts, what group of animals do frogs belong to among the following options: - four limbs - animals - fish - warm-blooded - reptiles - Amphibians - more abundant - mammals
The answer is:
Amphibians