Oceans are the great bodies of water which make up almost 71 per cent of the Earth's surface.Many people say that there are really three oceans_the Atlantic,the Pacific,and the Indian.Others add the Arctic Ocean,but most people consider this to be really part of the Atlantic in the north.Towards the South Pole is the Southern Ocean,surrounding Antarctica.Round the edges of the oceans are smaller bodies of water.

The average depth of oceans are usually 4000 metres.Oceans have great advantage over our lives.Without these there would be no life on Earth.The world would be a dry,barren desert with temperature over 100 degree celsius .

The importance of oceans:-

• They are the source of rain on which the world depends for crops and life.
• They regulate the Earth's temperature so that it is suitable for life.
• The ocean floor supplies some minerals,especially oil and gas.
• They provide transport across much of the world.
• They are a source of food_fish and selfish,seaweed and plankton.