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V: Coronary heart disease is caused by a buildup of plaque in the arteries that supply blood (with viscosity n) to the heart. For simplicity, let's assume that the artery is cylindrical with a radius of R. If plaque buildup reduces the radius of the artery by a factor of 4, by what factor does the flow rate change? The flow rate is now 1/256'h of the original. The flow rate is 1/16'h of the original. The flow rate is 4 times the original. The rate is 16 times the original. The flow rate is 256 times the original. VI: Sustained exercise can increase the blood flow rate of the heart by a factor of five with only a modest increase in blood pressure. This is a large change in flow. Although several factors come into play, which of the following physiological changes would most plausibly account for such a large increase in flow With a small change in pressure? A. Dilation of the smaller blood vessels to larger diameters. B. An increase in the viscosity of the blood. An increase in the oxygen carried by the blood. Contraction of the smaller blood vessels to smaller diameters. E. A decrease in the viscosity of the blood