In the context of respiration, what does diffusion specifically refer to?

Diffusion specifically refers to the process by which gases such as oxygen and carbon dioxide move across membranes, particularly in the lungs during respiration. This involves the spontaneous movement of these gases from areas of higher concentration to areas of lower concentration, allowing for the exchange of oxygen from the alveoli into the bloodstream and the removal of carbon dioxide from the blood into the alveoli to be exhaled. This fundamental process is essential for cellular respiration, as it enables the body to obtain oxygen and eliminate carbon dioxide efficiently, thus maintaining proper physiological function and homeostasis.