What is the process by which animals use oxygen to break down food for energy called?

The process animals use to break down food for energy utilizing oxygen is called cellular respiration. This biochemical process occurs in the cells of the organism and involves converting glucose (a product of food) and oxygen into carbon dioxide, water, and energy, which is stored in the form of ATP (adenosine triphosphate). Cellular respiration is crucial for producing the energy that fuels various cellular activities necessary for life.

In contrast, photosynthesis is the process used by plants to convert light energy into chemical energy, resulting in the production of glucose from carbon dioxide and water. Fermentation is an anaerobic process that occurs in the absence of oxygen, allowing organisms to produce energy without utilizing oxygen, typically resulting in byproducts like alcohol or lactic acid. Digestion refers to the breakdown of food into smaller, absorbable components but does not directly involve the breakdown of food for energy in the presence of oxygen. Therefore, cellular respiration is the correct term that encompasses the complete process of energy production using oxygen in animals.