Compare the structure and function of arteries and capillaries. which of the following best describes their differences? a) arteries are thick, rigid blood vessels that carry oxygenated blood from the heart, whereas capillaries carry deoxygenated blood. b) capillaries have thin walls to allow gas exchange, whereas arteries have thick walls to withstand high blood pressures. c) unlike arteries, capillaries are narrow so that their blood pressure is high, forcing blood to diffuse into surrounding tissue. d) unlike capillaries, arteries carry deoxygenated blood from tissues in the lungs, brain, and the rest of the body.