Question

Mixing of oxygenated and deoxygenated blood occurs in the heart of

• A. frog
• B. crocodile
• C. human
• D. bird

Answer 1

The correct option is A frog

Frog has three-chambered heart with two atria and a single ventricle. In frogs, both oxygenated and deoxygenated blood get mixed up in the single ventricle and the heart pumps out mixed blood. This is known as incomplete double circulation.

Human, crocodile and bird heart is four chambered with completely separate double circulation. There is no mixing of oxygenated and deoxygenated blood in the human heart.