Question

what do you mean by double why is it necessary ​

Answer 1

Answer:

Hope this helps you.

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.

Answer 2

Answer:

The question is not correct. There is no definition of double.

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