Pathology At a constant blood flow, an increase in the number of perfused capillaries improves the exchange between blood and tissue because of A Greater surface area for the diffusion of molecules B Faster flow velocity of plasma and red blood cells in capillaries C Increased permeability of the microvasculature D Decreased concentration of chemicals in the capillary blood 💡 Explanation At a constant blood flow, an increase in the number of perfused capillaries improves the exchange between blood and tissue because of ✓ Correct Answer: A. Greater surface area for the diffusion of molecules