(a) Define diffusion as the net movement of particles from a region of their higher concentration to a region of their lower concentration.
(b) Describe how diffusion is involved in gaseous exchange at the alveoli of the lungs and absorption of oxygen and release of carbon dioxide gas at the root hair cells.
(c) Define osmosis as the net movement of water molecules from a region of their higher water potential to a region of their lower water potential across a partially permeable membrane.
(d)Describe the effects of osmosis on plant and animal tissues
(e) Define active transport as the movement of substances from a region of their lower concentration to a region of their higher concentration with the expenditure of energy.
(f) Explain the role of active transport in the absorption of digested nutrients against a concentration gradient at the villi of the small intestines.