Focusing on the five human bodily senses, it became evident that all are dependent on water to function. The sense of hearing - distance mechanoreception - is used to detect movements in the fluid (air, water) surrounding the organism, the eye produces water and ‘cries’ as a defense mechanism, the nose smells by breathing in vapour and particles, the tongue produces saliva (liquid) to digest food, and the skin produces sweat to regulate body temperature.