Small Molecules Can Move Between Capillaries and Interstitial Fluid by _____

Question

Small molecules can move between capillaries and interstitial fluid by _____  
A) passive transport
B) active transport
C) endocytosis
D) diffusion
E) exocytosis

Accepted Answer

Small molecules can move between capillaries and interstitial fluid by diffusion, which is a passive process that occurs due to concentration gradients. Active transport requires energy, endocytosis and exocytosis involve the use of vesicles and are not likely to play a role in capillary exchange of small molecules.