Which best describes the difference between osmosis and diffusion? Osmosis is the movement of particles from a high to low concentration, while diffusion is the movement of water from a low particle concentration to a high particle concentration. Diffusion is the movement of particles from a high to low concentration, while osmosis is the movement of water from a low particle concentration to a high particle concentration. Diffusion is the movement of particles from a low to high concentration, while osmosis is the movement of water from a high particle concentration to a low particle concentration. Osmosis is the movement of particles from a low to high concentration, while diffusion is the movement of water from a high particle concentration to a low particle concentration.