The process by which animals obtain energy from food is known as cellular respiration. This biochemical process occurs within cells and converts food molecules, typically glucose, into energy stored in the form of adenosine triphosphate (ATP). Cellular respiration involves several stages, including glycolysis, the Krebs cycle, and oxidative phosphorylation. Oxygen is often required in aerobic respiration, while anaerobic processes occur in environments lacking oxygen. The energy produced is essential for various biological functions such as movement, growth, and reproduction. Efficient energy conversion is crucial for sustaining life in all animals, ensuring they meet their energy needs.