The velocity of blood is maximum in the:

Ans. is 'a' ie large veins (Ref: Ganong, 22/e, p584).The velocity of blood is inversely proportional to the total cross-sectional area at that point.Thus the velocity of blood is high in aorta, declines steadily in the smaller arteries and is lowest in the capillaries (The capillaries have 1000 times the total cross- sectional area of the aorta) The velocity of blood flow increases again as the blood enter the veins and is relatively high again in the vena cava, although not so high as in the aorta.