The whole body of salt water which covers the most of the Earths surface. The average salinity of ocean water is approximately three percent. Five oceans of the world are Atlantic, Pacific, Indian, Arctic, and Antarctic.
The ocean makes our planet a wonderful place to live. It gives us more than half of the oxygen we breathe. It regulates the climate, absorbs a quarter of the carbon that we put into the atmosphere every year, provides livelihoods for hundreds of millions of people.