During diffusion, molecules move a) in no predictable pattern. b) to points equidistant from the point of origin. c) from lower concentration to higher concentration. d) from higher concentration to lower concentration.

The answer is D.

The net movement of diffusion is the particles move from a region of higher concentration to the region of lower concentration, down the concentration gradient. This is the result of their random movement originally.

Diffusion is applicable for all fluid materials including gas and liquid. Diffusion will end when the concentration of the solute is same for both sides of the solution. We call this equilibrium.

If specifically talking about the movement of water molecules, that should be osmosis. It's very similar to diffusion just that its only for the water molecules.