Water
The world is not only hungry,but also is short of the water.This may sound strange for 70% of the surface of the use is covered by water.But 97% of this is sea water or soft water.Man can only use the other 3% fresh water that country rivers,lakes and from other ground and we can't ever use all of that because some of it isn't . What's worse, some of the fresh water has been polluted.Our need of water is increasing rapidly day by day. So we should take the measures to solve the problem. |