Osmosis it the net movement of water particles across a partially permeable cell membrane from a high concentration to a low concentration.
Diffusion is the net movement of particles of a gas or a solution from a high concentration to a low concentration.
The cytoplasm is a liquid gel and is where most chemical reactions for life take place. The cytoplasm is made up of chemicals dissolved in water inside a partially membrane. The cytoplasm contains concentrated solutions of salts and sugar.
Solutions inside cells are seperated from solutions outside cells, by the cell membrane.