It has a small molecule but its unequal charge allows it to dissolve almost any material. Liquid water holds a huge amount of heat energy and resists changes of state to solid or gas. When it freezes it becomes less dense and floats on liquid water, it also releases most of its heat energy into the surrounding water leaving it warmer. When water evaporates it carries heat energy with it, this cools the remaining water. The seas resist freezing and boiling.
Earth experiences a temperature range that allows most of the water to remain as liquid or solid.
Unequal heating of our planet by our sun moves water vapor over the planet distributing energy. Living creatures must acquire energy and store it. All life is composed of a basic unit- the cell. Sequences of the DNA called genes direct a complicated series of chemical pathways within the cell. These chemical pathways permit life.