AP BIOLOGY

Detailed explanation-1: -Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes “down the concentration gradient". The end result is an equal concentration, or equilibrium, of molecules on both sides of the membrane. At equilibrium, movement of molecules does not stop.

Detailed explanation-2: -Molecules move from an area of high concentration to an area of lower concentration until an equilibrium is met. The molecules continue to cross the membrane at equilibrium, but at equal rates in both directions.

Detailed explanation-3: -Diffusion refers to the process by which molecules intermingle as a result of their kinetic energy of random motion. It is the net movement of molecules or atoms from a region of high concentration to a region of low concentration.