Water

Simple, pure, life sustaining water.

"binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade "

"body of water: the part of the earth's surface covered with water (such as a river or lake or ocean); "they invaded our territorial waters"; "they were sitting by the water's edge""

"once thought to be one of four elements composing the universe"

"a liquid necessary for the life of most animals and plants"

Simple . . . . pure . . . . . life sustaining.