Water is a natural resource that can be found on Earth and is known as one of the primary causes of the Invasion of Earth, because the extraterrestrials who invaded Earth used it as fuel for their aircraft. Water is a chemical substance and has the chemical symbol of H2O (1 Hydrogen and 2 Oxygen atoms). Water covers approximately 71% of the Earth's surface. Water can appear in a liquid, solid, or gaseous state. (It is simply water when in liquid form, ice in solid form, and water vapor in it's gaseous state.) Water is also essential to humans and other lifeforms on the planet for drinking, bathing, and other uses necessary for survival.