Diffusion, osmosis, active transport

Diffusion, osmosis and active transport are all means by which particles move from one area to the next.

Diffusion is a form of passive transport and involves movement down a concentration gradient.   This means that particle move from an area of high concentration to low concentration.  Think of how the scent of perfume travels..........this is diffusion.

Osmosis is also a form of passive transport but refers to movement of water particles from high to low concentration but through a partially permeable membrane.

Active transport as the name suggests is "active".  It requires energy and this is where particles are moved against a concentration gradient, form low concentration to high concentration. This is the way glucose is absorbed by the body.