Freshwater refers to water that has low concentrations of dissolved salts, typically found in rivers, lakes, and streams. It is essential for drinking, agriculture, and supporting diverse ecosystems. Key sources of freshwater include glaciers, groundwater, and rainfall. Marine water, on the other hand, is saltwater found in oceans and seas, covering about 71% of the Earth's surface. It plays a crucial role in regulating climate and supporting marine life, including fish, coral reefs, and marine mammals. The balance between freshwater and marine environments is vital for the planet's health.