Assertion : There is no mixing of oxygenated and deoxygenated blood in the human heart.
Reason : Valves are present in the heart which allows the movement of blood in one direction only.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Answer

B

Explanation

There is no mixing of deoxygenated and oxygenated blood in human heart due to the presence of inter-atrial and inter-ventricular septum. These septa completely divide the atria and ventricles into right and left to avoid mixing of blood. The backflow of the blood is prevented by the presence of valves. The two atria are separated from the ventricles by menbranous valves. They allow the flow of blood from atria to ventricles and not in the backward direction. At the base of aorta and pulmonary artery, are present three membranous, pocket-shaped semilunar valves. These valves check the return of the blood to the ventricles.