The document discusses oceans and seas. It defines an ocean as a major body of saline water that covers approximately 71% of the Earth's surface. Oceans are very deep and include the Pacific, Atlantic, Indian, Arctic, and Southern Oceans. Seas are smaller bodies of water located where land and ocean meet, and are partially enclosed by land. Examples include the South China Sea, Mediterranean Sea, and Arabian Sea. The color of the oceans is largely due to how light from the sun reflects off ocean waters.