The rate at which blood flows through the human body changes in response to many factors. which statement describes one of these factors and its effect on blood flow? a. the narrowing of blood vessels increases pressure and leads to faster blood flow. b. high blood viscosity increases the resistance in the blood vessels and leads to slower blood flow. c. low blood ph decreases the rate of diffusion through the blood vessels and leads to slower blood flow. d. the changing of the shape of red blood cells to a crescent shape decreases resistance and leads to faster blood flow.