Question

define the mechanism of osmosis and give its importance

Answer 1

Osmosis is the spread of water through semi-permeable material Therefore, the solution moves from a lower concentration level to a higher concentration level. Even during osmosis, soluble particles do not move.

The importance: 
Osmosis is important in human beings both the biological processes occurring in the body as well as day to day life. 
Osmosis also influences the distribution of nutrients and the release of metabolic waste products into and out of the body. 

Answer 2

HERE IS YOUR ANSWER...
Osmosis is the movement of a solvent across a semipermeable membrane toward a higher concentration of solute (lower concentration of solvent). ... When a cell is submerged in water, the water molecules pass through the cell membrane from an area of low solute concentration to high solute concentration.

The biological importance of osmosis is that it facilitates the distribution of essential nutrients in the body and the excretion of metabolic waste products. Cells have semipermeable membranes, and osmosis makes it possible for liquid solvents to pass through these cell membranes.

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