Why is is the heart a double pump?

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Answers:
the heart is a double pump because the blood is pumped through 2 sections(atriums) to oxegenate the blood. when the blood passes through one atrium, it is pumped again through the next one.
The heart is not always a double pump - in some animals the double pump is not the case.

Although, surrounded by Humans, the double pump works for each of the sides. The right side pumps it to the lungs and exchanges the co2 and such with oxygen and the left side pumps it to other parts of the body.

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Much more efficient than single circulatory systems found within other animals (eg fish)

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