Define respiration.

Respiration is the biochemical process by which living cells break down food molecules, such as glucose, to release energy for carrying out various life processes.

This process may occur in the presence of oxygen (aerobic respiration) or in its absence (anaerobic respiration). In aerobic respiration, oxygen is used to completely break down glucose into carbon dioxide and water, releasing a large amount of energy.

Respiration takes place inside the cells, mainly in the mitochondria, and is essential for activities such as growth, movement, repair, and maintenance.

In simple terms, respiration is the process of releasing energy from food within the cells.