- Water is essential for life and has many important properties due to its polarity and ability to form hydrogen bonds. It acts as a solvent, coolant, and transport medium within organisms. - The polarity and hydrogen bonding of water molecules gives water high heat capacity, specific boiling and freezing points, and allows it to dissolve many substances. Hydrogen bonding also contributes to water's cohesive and adhesive properties. - Water's properties help sustain life and allow organisms to regulate temperature and transport nutrients and wastes. However, acid rain can lower the pH of bodies of water and damage ecosystems.