An ocean (from Greek Ωκεανός, Okeanos (Oceanus)) is a major body of Seawater (salt water). The Earth's oceans cover approximately 71% of the Earth's surface, 361,000,000 square kilometres (139,000,000 sq mi), and can be as deep as of 10,923 metres (6.787 mi). Scientists estimate that 230,000 marine life forms of all types are currently known, but the total could be up to 10 times that number.[1]




