Answer:
Because blood is pumped to the lungs, where we can find fresh blood. The blood in the RIGHT side of the heart is deoxygenated. The left side of the heart is the one which receives oxygenated blood. It comes directly from the pulmonary vein. It is further pumped into the aorta. The right side of the heart receives deoxygenated blood from the phenomenon called vena cava. Then, it’s pumped into the pulmonary vein.
