Which of these explain(s) the diffusion of oxygen from alveoli to blood?
Low concentration of oxygen in the blood.
High concentration of oxygen in the alveoli.
Movement of particles from higher concentration region to lower concentration region is called diffusion. During inspiration, the concentration of oxygen inside the alveoli is higher than that of blood capillaries whereas the concentration of carbon dioxide in blood capillaries is higher than that of alveoli. As a result oxygen from the alveoli diffuses to the capillaries and the carbon dioxide from capillaries diffuses to the alveoli.