The chemical composition of water is H2O, which means each molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. This simple yet crucial compound is essential for all known forms of life. The unique properties of water, including its polarity, high specific heat, and solvent capabilities, enable it to play critical roles in biological processes, such as temperature regulation and nutrient transport. Water is commonly found in three states: liquid, solid (ice), and gas (water vapor), which is essential for climate regulation and various ecological cycles on Earth.