Beyond its relevance as a structural composite of all life forms it is of interest that all human experience of the outside world is mediated through water. Although I use the term water freely, it is the primary constituent of all biological fluids, albeit it with small percentages of solutes.
Sight depends upon light transmitted through water, such as the surface fluid on the conjunctiva, the lens, plus the aqueous and vitreous humours. Accurate focus depends upon all these layers
Sound is mediated through water in the cochlea.
Smell and taste is, of course, a sequel to the dissolution of particles in fluids on the surface of the tongue and olfactory membrane.
Touch is dependent upon the succulence surrounding the receptors in the skin.
Humans as individuals depend upon, as sine qua non, two over-riding capabilities. The one is the capacity to dissipate energy (which I won’t enlarge upon here) and the other is as a balancing machine.
Balance (which can also be considered a sense) is mediated by the water in the semi-circular canals. It is interesting that the most important sense, the sense of Gravity (or balance) is so taken for granted that it is ignored !
Procreation is mediated entirely through water. Insemination uses watery fluid as its transport medium and the foetus is nurtured entirely in a water-filled container.
The active interface with oxygen is via dissolution in water, whilst the other “fuel”, food, depends .upon water for its transit from the gut into the milieu interior
Mucous is the other great constituent of biological function, and can be considered “anti-water”, but enlargement on that will not be pursued here.