Respiration is the process by which organisms exchange gases with their environment. It involves the metabolic exchange of oxygen and carbon dioxide. There are two types of respiration: aerobic respiration, which uses oxygen to break down glucose and release energy; and anaerobic respiration, which breaks down glucose without oxygen. Respiration occurs through breathing in the lungs, gas exchange in the alveoli, and breathing out carbon dioxide in humans. In plants, photosynthesis occurs during the day to take in carbon dioxide and release oxygen, while cellular respiration takes place at night to take in oxygen and release carbon dioxide. Respiration is essential for life and fuels cellular activities while maintaining homeostasis.