Which of the following is NOT part of the passive transport process?

Step 3: Define each term: Simple diffusion is the movement of small, nonpolar molecules directly through the lipid bilayer. Osmosis is the diffusion of water molecules across a selectively permeable membrane. Facilitated diffusion involves the use of protein channels or carriers to move molecules across the membrane, still without energy. Endocytosis, however, is an active transport process that requires energy to engulf substances into the cell via vesicles.

Step 4: Compare the characteristics of passive transport processes (simple diffusion, osmosis, facilitated diffusion) with endocytosis. Note that endocytosis does not fit the definition of passive transport because it requires energy input.