Question

suggest why it is an advantage for blood to flow very slowly through capillaries?​

Answer 1

Blood flow is slowest in the capillaries, which allows time for exchange of gases and nutrients. Resistance is a force that opposes the flow of a fluid. In blood vessels, most of the resistance is due to vessel diameter. As vessel diameter decreases, the resistance increases and blood flow decreases.

Answer 2

Answer:

Recall that velocity of blood flow is dependent on the cross sectional area. Although the capillaries are the smallest blood vessel in diameter, blood flow through the capillary bed is slow. This is because the capillaries are more numerous than any other blood vessel hence their total cross sectional area is large.