Blood Flow Slows in Capillaries Due to Their ________

Question

Blood flow slows in capillaries due to their ________.  
A) valves
B) small diameters
C) large collective cross-sectional area
D) small collective cross-sectional area
E) short lengths

Accepted Answer

Capillaries have a large collective cross-sectional area compared to the arteries and veins leading to and from them. This larger area allows for slower blood flow, facilitating exchange of gases, nutrients, and waste products between blood and tissues.