Work

The application of a force on an object that results in the displacement of the object.

The force must be applied, at least in part, in the same direction as the displacement.

Cellular Respiration

A series of metabolic reactions, taking place at that the cellular level, that convert organic matter (food) into a usable form of energy.

There are two types of cellular respiration: aerobic (in the presence of oxygen) and anaerobic (without oxygen).