Lakes are large bodies of freshwater surrounded by land. They can be found in various sizes and depths and are often formed by glaciers, rivers, or volcanic activity. Lakes provide habitats for many species of fish, birds, and plants, making them important ecosystems. Oceans, on the other hand, are vast bodies of saltwater that cover about 71% of the Earth's surface. They are divided into five main regions: the Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean. Oceans play a crucial role in regulating the planet's climate and supporting marine life.