Facilitated diffusion requires a. membrane proteins b. transport proteins c. membrane pouch d. energy

The answer is b. transport proteins.

Facilitated diffusion is the process of passive transport, which means without using of energy, of ions and molecules across a cell membrane. Although, this process does not require energy such as active transport, transport proteins are required. The role of transport proteins in facilitated diffusion is to provide a hydrophilic route within hydrophobic lipids of the membrane, and that way facilitate ions and molecules to cross the membrane.