What is the term for the exchange of respiratory gases between an organism and its environment?

The term that accurately describes the exchange of respiratory gases between an organism and its environment is "gas exchange." This process involves the uptake of oxygen from the environment and the release of carbon dioxide as a waste product of cellular respiration. In animals, gas exchange typically occurs in specialized structures such as lungs or gills, where oxygen diffuses into the bloodstream while carbon dioxide is expelled.

In contrast, photosynthesis refers specifically to the process by which plants, algae, and some bacteria convert light energy into chemical energy, primarily in the form of glucose, using carbon dioxide and water. Cellular respiration is the metabolic process by which organisms convert glucose and oxygen into energy, carbon dioxide, and water, but it primarily takes place inside cells rather than as an exchange with the environment. Metabolism is a broader term that encompasses all chemical reactions within an organism, including both the breakdown of molecules for energy and the synthesis of compounds, but it does not specifically refer to the exchange of gases with the environment. Thus, "gas exchange" is the most precise term for describing the respiratory process involving the transfer of gases.