Gas exchange structures are specialized parts of organisms that facilitate the transfer of gases, primarily oxygen and carbon dioxide. In animals, these structures include the lungs, gills, and tracheae, which allow for efficient respiration. In plants, gas exchange occurs through small openings called stomata on leaves, enabling the uptake of carbon dioxide for photosynthesis and the release of oxygen. These structures are designed to maximize surface area and minimize diffusion distance, enhancing the efficiency of gas exchange. For example, the alveoli in the lungs provide a large surface area for oxygen to enter the bloodstream, while gill filaments in fish allow for the absorption of oxygen from water.