Question

all of the following are forms of passive transport except— a osmosis. b facilitated diffusion. c a protein pump. d diffusion.

Explanation:

Passive transport is the movement of substances across the cell - membrane without the use of energy. Osmosis is the diffusion of water across a semi - permeable membrane, facilitated diffusion uses transport proteins to move substances down their concentration gradient, and diffusion is the movement of substances from an area of high concentration to an area of low concentration. All these are passive transport. A protein pump, however, moves substances against their concentration gradient and requires energy (ATP), which is active transport.

Answer:

C. a protein pump