Answer
Velocity of blood flow is fastest in the aorta and the arteries.
Work Step by Step
Velocity of blood flow is inversely related to the cross-sectional area of the conduit(s). As blood vessels get farther and farther from the heart, they branch repeatedly and thus progressively increase the total cross sectional area of the vascular system, As a result, blood flow becomes slower, and slower, as the blood gets farther and farther away from the heart.--that is from aorta to arteries to capillaries. Velocity is slowest in capillaries, where the total cross-sectional area is greatest. Velocity increases from capillaries to venules to veins, as total cross-sectional area decreases.
