Capillaries permit the exchange of nutrients and wastes between cells and the blood because of which feature of their structure? A. adjacent endothelial cells are separated by gaps which allow free exchange between blood and interstitial fluid. B. they are in close proximity to most cells. C. they have a single layer, the tunica intima, consisting of a single layer of endothelial cells in their walls. D. their endothelial cells have pores (windows) to allow the rapid movement of water and solutes.
Option C. Capillaries permit the exchange of nutrients and wastes between cells and the blood because they have a single layer, the tunica intima, consisting of a single layer of endothelial cells in their walls.
