Question

what type of circulatory system is seen in frog and pigeon ?

Answer 1

Double circulation. But frog has 3 chambered heart

Answer 2

Amphibians have a closed circulatory system that forms a double circuit through a three-chambered heart. In particular, deoxygenated blood enters the heart at the right atria and is pumped into the single ventricle, where it exits the heart into the pulmocutaneous or systemic circulation.