Oceans

From Environmental Technology

Oceans cover more than 75 per cent of the earth's surface. The different oceans merge into one another, forming the largest habitat on earth. The three major oceans of the world are the Pacific, the Atlantic and the Indian Ocean. The Arctic ocean surrounds the North Pole while the Southern Ocean (really the southern portion of the Atlantic and Pacific Oceans) surrounds the continent of Antarctica.

References

http://www.panda.org/news_facts/education/middle_school/habitats/oceans/index.cfm