Describe double circulation of blood in human beings. Why is it necessary?

(N/A) The human heart is divided into four chambers: the right atrium,the right ventricle,the left atrium,and the left ventricle.
Flow of blood in the heart:
The heart has superior and inferior vena cava,which carry deoxygenated blood from the upper and lower regions of the body respectively and supply this deoxygenated blood to the right atrium of the heart.
The right atrium then contracts and passes the deoxygenated blood to the right ventricle through an atrioventricular aperture.
Then,the right ventricle contracts and pumps the deoxygenated blood into the two pulmonary arteries,which carry it to the lungs where the blood becomes oxygenated. From the lungs,the pulmonary veins transport the oxygenated blood to the left atrium of the heart.
Then,the left atrium contracts and the oxygenated blood enters the left ventricle through the atrioventricular aperture.
The blood then passes into the aorta from the left ventricle. The aorta gives rise to many arteries that distribute the oxygenated blood to all regions of the body.
Therefore,the blood passes twice through the heart in one complete cycle. This is known as double circulation.
Importance of double circulation:
The separation of oxygenated and deoxygenated blood allows for a more efficient supply of oxygen to the body cells. This efficient system of oxygen supply is essential for warm-blooded animals like human beings.
Warm-blooded animals must maintain a constant body temperature by regulating heat. Hence,they require more $O_2$ for cellular respiration to produce the energy needed to maintain their body temperature. Thus,the circulatory system of humans is highly efficient due to the double circulatory heart.