All is Born of Water, All is Sustained by Water

More than perhaps any other element of life on earth, water makes possible the existence of all living organisms. When two hydrogen atoms fasten to one oxygen atom, they create an asymmetrically shaped molecule. The hydrogen atoms are drawn together slightly on one side of the oxygen atom, creating a positive charge on one side of the water molecule and a negative charge on the other. The opposite charges create an effect similar to a magnetic attraction that bonds water molecules to neighboring water molecules and to other substances. This remarkable chemical circumstance knits together the fabric of life.

The aggregate accumulation of water molecules is a substance that flows at normal temperatures. Most other fluids i.e. milk and blood are water-based. They are made of non-liquids suspended in water.

Without the motion and the distribution system that moving water provides, the elements of life would never connect, their commingling under sunlight would not produce the complicated carbon compounds that lead eventually to cells, cells would not be able to gather as the moist organized and specialized cell colonies we call tissue, their aggregation would have no exchanging processes, no supply systems of food and breath, the eye would not see, the brain would not compute, the muscle would not move.

By and large, the characteristics of the water molecule that make it life-giving are freakish properties. They are, more often than not, exceptions to basic chemical rules.

Almost every other substance becomes heavier, smaller, and denser as it changes from a liquid to a solid. But water expands and grows lighter, so that ice floats. If that does not seem remarkable, it should. If water acted like other substances, its solid form, ice, would sink. The floor of the sea and the bottoms of lakes would accumulate ice. Gradually, winter after winter, the ice would lock up more and more water until there would be none running free on the planet. There would be no life on earth.

More substances can be dissolved by water than by any other material. The water molecule, with its magnet like opposite charges, is able to carry other substances suspended within itself, making it a nearly universal solvent.
Water is able to climb of its own accord, a feat that results in capillary action in soils and in plants. Without this characteristic, water would not travel from the deepest root tip to the highest leaf. There would be no internal flow of nutrients in complicated organisms, and thus no complicated organisms. The trick occurs because the attraction of water molecules to themselves and to other molecules is so strong that they are drawn upward from one foreign molecule to another, always pulling along the adjacent water molecules. The climb is halted only by gravity.
Great amounts of heat can be absorbed by water, making seas, rivers, lakes, and clouds vast energy storage banks. The release of stored heat from the ocean, for example, moderates climates, making coastal winters milder than those only a few miles inland.

Human blood, excluding the cells and proteins, has the same general composition as seawater.

Through a fortunate accident, Planet Earth is the right distance from the sun to make the existence of life-giving water possible. Closer to the sun the heat is so intense that water would be vaporized; farther away, water would be permanently frozen. Only Mars, of the other planets in the solar system, is in the narrow temperature band in which water can exist in all three states. But only Earth is blanketed by a living, water-built biosphere, in which the lifesource itself seems to issue from water's evaporation, precipitation, runoff, seepage, transpiration from plants, respiration from animals, melting, freezing, and flowing. Earth, as far as we know, is the only water planet.