Diffusion is a key mechanism for transporting vital substances throughout the body. Take oxygen, the essential gas for energy production. With each inhalation, we produce a high concentration of oxygen in our lungs. The tiny blood vessels embedded in the lungs have a relatively low amount of oxygen. That allows the vital gas to “diffuse” from the lungs to the blood, and then, for the same reason, from the blood to individual cells throughout the body. Such directed movement results from random collisions, tending to transport oxygen molecules from areas of high to low oxygen concentration.
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