Question

which mechanism requires energy?

○ diffusion of oxygen into a red blood cell

○ diffusion of ions through a potassium channel

○ osmosis

○ exocytosis

Explanation:

Diffusion (oxygen into red blood cells, ions via potassium channels) and osmosis are passive transport processes that do not require energy, as they move substances down concentration gradients. Exocytosis is an active transport process where cells release large molecules via vesicle fusion with the membrane, which requires energy (ATP).

Answer:

D. exocytosis