Question

the valves are present auricles and ventricles. why

Answer 1

Valves ensure that blood does not flow backwards when the ventricles contract, i.e. it ensures that the blood flows only in one direction.

Answer 2

Explanation:

Valves between the atria and ventricles open and close passively according to changes in pressure in the chambers. The valve helps to preventing backward flow of blood.

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