Final answer:
Osmosis is the movement of water through a semipermeable membrane according to its concentration gradient across the membrane. Facilitated transport is a mechanism that assists in the movement of substances across membranes without the use of cellular energy.
Step-by-step explanation:
Osmosis is the movement of water through a semipermeable membrane according to the concentration gradient of water across the membrane, which is inversely proportional to the solutes' concentration. While diffusion transports material across membranes and within cells, osmosis transports only water across a membrane and the membrane limits the diffusion of solutes in the water. Facilitated transport, on the other hand, involves the movement of materials across a membrane with the assistance of transmembrane proteins. This transport mechanism facilitates the movement of substances down a concentration gradient without the use of cellular energy. The integral proteins involved in facilitated transport function as either channels or carriers to facilitate the passage of substances.