The process that uses oxygen in plants, algae and animals is cellular respiration. In this process, oxygen is used to decompose glucose into energy that is used for energy, growth and other metabolic processes. Aside from energy, this process also results in the creation of carbon dioxide and water.
Animals take up the required oxygen through their lungs, while plants and algae obtain oxygen through the stomata in their leaves and through their roots. The concept of "burning" energy also comes from this process; in chemistry, the combination of any compound with oxygen forms a combustion reaction. As such, this process is chemically similar to many other burning processes, such as the burning of wood that results in the releasing of heat.