Gas exchange refers to the process by which organisms take in oxygen and release carbon dioxide. In plants, gas exchange occurs through small openings in the leaves called stomata, while in animals it occurs in the respiratory system through processes such as breathing and diffusion of gases in the lungs. This exchange of gases is essential for cells to carry out aerobic respiration and obtain the energy they need to survive. In addition to oxygen and carbon dioxide, other gases such as nitrogen and water vapor may also be exchanged during this process. Understanding gas exchange is crucial in various fields such as biology, environmental science, and medicine.