Blood circulation in a mammal is said to be double because?

Blood circulation in a mammal is said to be double because?

A it passes twice through the heart in a complete circuit
B it moves in both arteries and veins
C it circulates in both the heart and other organs
D the heart contains auricles and ventricles

jamb 2021 biology

The correct answer is A. it passes twice through the heart in a complete circuit

It is called a double circulatory system because blood passes through the heart twice per circuit.

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