Many astrologists and researchers have been searching life on different planets. Researches have been made to find life with water on Mars, Saturn, and other planets. However, there is only the planet in this universe having life and water is 'Earth.' Earth has its unique characteristics which has made it unique from other planets. Some important characteristics are: Earth is the only planet in which water is available in three forms. These three forms are solid, liquid and gas.
Water is a tranparent, colourless, odourless which forms seas, oceans, lakes, rivers and the fluids of most living organisms. Water is written in chemical formula as H2O. This chemical formula shows that it contains one oxygen and two hydrogen atoms.
Water is an essential requirement for every kind of living organism on this earth. Water is so important for our body without which we cannot live. Water is the most abundantly available on our planet. About 75% of our earth is covered in water. That's why our earth is called as a watery place.
Not only water is available in the form of oceans or rivers, it also exists in the air as water vapour, lakes, glaciers and icecaps and even in our body and all animals. It is surprise to know that water never sits, it always moves from one place to another and from one form to another which is well known as 'Water Cycle.'
Water is considered to be an essential resource for agriculture, industrial, recreational and environmental activities.
The vast majority of water on the earth's surface is saline water (the water which contains salt). If we talk about saline water, we talk about the oceans. The water that comes from skies and moving into the streams, lakes, rivers and ground water provide freshwater to people that they need everyday.

You may be surprised to know that the underground water is more fresh than the water in liquid form on the surface. Perhaps, you have seen the flowing water in the rivers, in fact some of the water comes from underground into the riverbeds.
Most of the water available on earth's surface are used by people, animals and plants. Streams and lakes are the most optical part of the water cycle. They are the great places where people go there to have fun and for relaxation. Fresh water represents about 3 % of all water on earth and about 0.29 % is for lakes and streams fresh water.
Governments and engineers have built systems in order to store water and use it when they need it or when the supply of water is not sufficient for people.
Bibliograhy: https://water.usgs.gov/edu/earthhowmuch.html





