Answer: By the process of diffusion.
Explanation: Diffusion, is a process that refers to the net movement of molecules from a region of high concentration to one of lower concentration. The oxygen you inhale, the air then passes across the thin lining of air sacs and into the blood vessels of your body. This is known as diffusion as I listed. The oxygen in the blood is now being carried around the body in the bloodstream, reaching every cell. When oxygen passes into the bloodstream, carbon dioxide leaves it as well.
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- Aaliyah