Answer:
(a) Semi-permeable membrane:
A semipermeable membrane is a membrane that only allows the movement of solvent molecules but restricts the movement of solute particles across the membrane.
(b) Osmosis:
The process of movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane is called osmosis.
When two nearby concentrations are different, materials will tend to spread out to equalize the concentration. For example, if you put a drop of food colouring in some water it will gradually spread through the whole water.
