What is osmosis: Osmosis is the diffusion

Osmosis is the diffusion of water molecules, down the concentration gradient, through a partially permeable membrane. The water moves fro the area of high concentration of water to low concentration water. Active transport is the movement of solutes from an area of low concentration to high concentratio so against the concentration gradient. Osmosis is the movement of water from an area of high concentration to an area of low concentration. Water moves through the xylem in a stream called a transpiration stream, up to the leaves of the plant. Diffusion, osmosis and active transport are all transport processes. Diffusion refers to the movement of any molecules/ions apart from water whereas osmosis refers to the transport of only water. In summary, the loop of Henle is surrounded by tissue fluid which has a high concentration of ions in it. This causes water to move out of the descending limb by osmosis . This produces a more concentrated filtrate because of this, ions move out of the loop in the thin ascending limb.