Question

why is it necessery to seperate oxygenated and deoxygenated blood in mammals and birds​

Answer 1

Answer:

as our body cells are aerobic cells ( cells which use oxygen for respiration )

Answer 2

Mammals and birds are warm blooded animals.This means that they can control their body temperature and they need not to depend on environment for body temperature regulation.Because of this birds and animals need optimum oxidation of glucose which is possible with good supply of oxygen. Four chambered heart in birds and mammals in ensure that deoxygenated blood do not get mixed with oxygenated blood.