(i) What is double circulation? (ii) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?

Question :(i) What is double circulation?
(ii) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?

The correct answer is -(i) Double circulation is the circulation of blood through the heart twice during one complete cycle of the body. It is a type of circulation in which the blood passes through two different circuits of the body, namely, pulmonary circulation and systemic circulation. (ii) The separation of the right side and the left side of the heart is useful as it allows the oxygenated and deoxygenated blood to remain separate, which helps in maintaining the oxygen concentration in the body. In mammals and birds, the separation of the heart into four chambers helps to increase the efficiency of oxygen delivery to the body tissues. The right side of the heart receives the deoxygenated blood from the body and pumps it to the lungs for oxygenation. The left side of the heart receives the oxygenated blood from the lungs and pumps it to the rest of the body. This separation ensures that the oxygen-rich and oxygen-poor blood do not mix, and the oxygenated blood is delivered efficiently to the body tissues.