Question

what is meant by diffusion​

Answer 1

Diffusion" is the gradual movement/dispersion of concentration within a body, due to a concentration gradient, with no net movement of matter. An example of a process where both bulk motion and diffusion occur is human breathing.

Answer 2

Diffusion is the movement of a substance from an area of high concentration to an area of low concentration.

Diffusion happens in liquids and gases because their particles move randomly from place to place. Diffusion is an important process for living things; it is how substances move in and out of cells.