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How does a scuba diver breathe underwater?
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A scuba diver breathes by inhaling air from the surface, then exhales it into the water. The diver's lungs are filled with oxygenated air, which is circulated throughout the body and used for breathing. As the diver descends deeper into the water, the pressure of the water increases, forcing more air out of the lungs. This process is called 'decompression', and it allows the diver to safely reach greater depths.