Diffusion is a process in which the molecules intermingle due to their kinetic energy and movement of molecules is from higher concentration to lower concentration. Osmosis is a process in which the water molecules move from lower solute concentration to higher solute concentration through a semi-permeable membrane. Digested food can pass into the blood vessels in the wall of the small intestine through the process of diffusion and water present in the ingested food is absorbed by the process of osmosis.