Our earth is the only planet in the solar system which has water in abundance; hence, it is often called a ‘watery Planet’.
About 71 % of the earth’s surface is covered by water.
Oceans form a single, large, continuous body of water encircling all the landmass of the earth.
They account for four- fifth of the Southern Hemisphere and three fifth of the Northern Hemisphere.
They contain 97.2 percent of the world’s total water.
There are four principal oceans in the world which are separated largely on the basis of their geographical locations.
These are the Pacific Ocean, the Indian Ocean, the Atlantic Ocean and the Arctic Ocean.
All the other seas, inland seas or the arms of the oceans, are counted within these four main oceans.
The Relief of the Ocean Basins
There are mountains, basins, plateaus, ridges, canyons and trenches beneath the ocean water too.
These relief features found on the ocean floor are called submarine relief.
The Ocean basins are broadly divided into four major sub-divisions.
(C) Abyssal plains
(D) The ocean deeps