Answer: D) Cellular Respiration
Cellular Respiration is the process of breakdown of sugar to form energy which required by the body for the various activities of the cell.
The respiration could either be an aerobic or an anaerobic, if it takes place in the presence of oxygen then it is called aerobic respiration and if it occurs in absence of oxygen then it is called anaerobic respiration. The ultimate aim of respiration is to produce ATP which is used by the cell.