No, humans cannot breathe in water. Our lungs are designed to extract oxygen from the air, not from water. The lining in our lungs is adapted to handle air rather than water, and our lungs do not have enough surface area to absorb enough oxygen from water.
Although humans cannot breathe underwater, there have been experiments with humans breathing other liquids, like fluorocarbons. This is known as liquid breathing, and it involves replacing the air in the lungs with a liquid that can deliver oxygen to the bloodstream. However, this is still very experimental and not yet practical for everyday use.
Fish, on the other hand, can breathe underwater because they have gills that are specifically designed to extract oxygen from the water. Gills have a large surface area that allows them to absorb oxygen from the water efficiently.
