Being underwater REDUCES the ability to localize sound. This is because, the resonance frequency of the external ear is reduced when the outer ear canal is fill with water. The presence of the water - air interface when one is under water and the reduction in the impedance matching ability of the middle ear also contribute to the reduction in one's ability to localize sound underwater.
An enzyme called amylase breaks down starches (complex carbohydrates) into sugars, which your body can more easily absorb. Saliva also contains an enzyme called lingual lipase, which breaks down fats.
