The document discusses the water cycle and distribution of water on Earth. It notes that 70% of Earth's surface is covered by water, with 97% being saltwater in oceans and 3% being freshwater. Most freshwater is frozen in ice caps and glaciers, with only 0.5% available for use by humans and other land organisms. The water cycle replenishes freshwater supplies through precipitation and evaporation. Conservation efforts can help ensure adequate water resources for all living things.