JAMB - Biology (1983 - No. 30)
Which of the following statements on the mammalian circulatory system is NOT true?
Blood in the pulimonary artery is richer in oxygen content than blood in the pulmonary vein
The blood in the hepatic portal vein is the richest in food substance
Blood flow is controlled by valves in the veins
Arteries are generally thicker and larger than veins
Fibrin helps in the formation of blood clot