What is meant by double circulation? What is its significance?

(N/A) Double circulation is a process during which blood passes twice through the heart during one complete cycle. This type of circulation is found in amphibians,reptiles,birds,and mammals. In birds and mammals,the heart is completely divided into four chambers: the right atrium,the right ventricle,the left atrium,and the left ventricle.
The movement of blood is divided into two parts:
$1$. Systemic circulation: It involves the movement of oxygenated blood from the left ventricle to the aorta,which distributes it to the tissues. Deoxygenated blood is then collected by veins and returned to the right atrium.
$2$. Pulmonary circulation: It involves the movement of deoxygenated blood from the right ventricle to the pulmonary artery,which carries it to the lungs for oxygenation. Oxygenated blood is then returned to the left atrium via pulmonary veins.
Significance of double circulation:
The separation of oxygenated and deoxygenated blood allows for a more efficient supply of oxygen to the body cells. It ensures that the tissues receive highly oxygenated blood,which is essential for maintaining high metabolic rates in birds and mammals.