Water is essential to all living things on Earth. It is due to water's strong ability as a solvent that it is seen as a strong indicator of the presence of life.
Water is composed of two hydrogen atoms and one oxygen atom. The oxygen atom is very electronegative, so it holds the two electrons from the hydrogen atoms in its outer shell, giving the oxygen end of the molecule a negative charge. The hydrogen end of the molecule has a positive charge. This means water is a polar compound and will be attracted to a multitude of molecules and able to dissolve a range of materials. Water is so good at dissolving so many things that it has been given the label "the universal solvent," indicating that there aren't too many things water won't dissolve. It is this ability to dissolve many substances that makes it a valuable commodity to living things, such as human beings.
Our bodies are composed 70% of water. Without water, the cells of our bodies could not conduct life processes. It is in the water solution that many molecules such as glucose, oxygen, and carbon dioxide are processed and utilized for necessary daily tasks.