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

Explanation:

During a single cycle blood goes twice in the heart which is known as double circulation. It is necessary in human being to separate oxygenated and de-oxygenated blood because this makes their circulatory system is more efficient and helps in maintaining constant body temperature.

The deoxygenated blood is pumped by the right ventricle into the lungs for oxygenation.  It is necessary for a human being to separate oxygenated and de-oxygenated blood because this makes their circulatory system is more efficient and helps in maintaining constant body temperature.

the andrews is b

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