What are the differences between diffusion, active transport and osmosis?

Diffusion is a passive process, this means that no energy is required, where there is a net movement of particles from an area of high concentration to an area of low concentration down the concentration gradient. Osmosis is also a passive process but instead this is a net movement of water molecules from an area of high concentration to an area of low concentration gradient down a water potential gradient across a selectively permeable membrane. Active transport is an active process, this means that energy is required, this energy is provided by the breakdown of ATP. Active transport is the net movement of particles from and area of low concentration to an area of high concentration against the concentration gradient via a carrier protein.