Question

What is double circulation and single circulation ?

Answer 1

A Single Circulatory System is a simple loop in which blood flows: Heart > Gills > Body > Heart. A Double Circulatory System is a double loop in which blood flows: Heart > Lungs > Heart > Body > Heart.

Answer 2

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It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart. The left pump sends the newly oxygenated blood around the body.