Question

Describe double circulation in human beings. Why is it necessary?NCERT Class XScience - ScienceChapter_Life Processes

Answer 1

It occurs in heart when the blood passes through the heart 2 times firstly the deoxygenated blood comes from whole of the body by superior and inferior vena cava and goes to right atrium and then to right ventricle then the blood goes into the lungs by pulmonary artery exchange of gases takes place and the deoxygenated blood is converted to oxygenated blood and goes to the left atrium and left ventricle by the pulmonary vein and by aorta the oxygenated blood is transferred to whole body

It is necessary to survive as the carbon dioxide if remains in our body could be fatal to us ,the cells present in our body needs oxygen to perform their activities and it's depletion can lead to death.