Explanation:

A root's four major functions are 1) absorption of water and inorganic nutrients, 2) anchoring of the plant body to the ground, and supporting it, 3) storage of food and nutrients, 4) vegetative reproduction and competition with other plants.
Justification: The root takes in oxygen present in the soil by the process of diffusion. Oxygen diffuses into the root hairs and passes into the other cells of the root.
And carbon dioxide released by the root cells diffuses into the soil. Since the root is involved in the exchange of gases, if the root of a land plant remains waterlogged for long, the plant dies.