Osmosis is a passive process and happens without any expenditure of energy.
It involves the movement of molecules from a region of higher concentration to the lower concentration until concentrations become equal on either side of the membrane.
Examples of osmosis are: If we put a raisin in water. it swells up the next morning due to the movement of water from the surroundings to inside the raisin, osmosis can also be seen inside the human body as most of the nutrients are reabsorbed from the small intestine and large intestine by process of osmosis.
