What makes up 3/4 of the Earth's surface? That's right, water! Water is a polar molecule. This is because the electrons are closer to the oxygen atom, and farther away from the 2 hydrogen atoms. Therefore, the oxygen has a net negative charge and the hydrogens have a net positive charge. The end that the two hydrogen atoms are on have a slightly positive dipole, which the oxygen end has a slightly negative dipole. Water molecules are held together with weak hydrogen bonds, but because there are so many of them, collectively they are very strong. As a result, water is very stable.
Water is a very good temperature regulator because a lot of energy is needed to turn liquid water into gas (breaking of a water lattice). So, water is stable over a wide range (0-100 degrees Celsius). Water can also dissolve any ionic compound. The reason for this is that the polarity of water is able to break the bonds between ionic compounds, because positives and negatives attract.
