Freshwater environments include rivers, lakes, ponds, and wetlands. These ecosystems are characterized by low salt concentrations and support a variety of plant and animal life, such as fish, frogs, and water lilies. Freshwater habitats are crucial for drinking water, agriculture, and recreation. Marine environments encompass oceans, seas, and coral reefs, which have higher salt concentrations. These vast ecosystems are home to diverse species, including whales, sharks, and sea turtles. Marine environments play a vital role in regulating the Earth's climate and supporting global food chains.