1. What is the hydrosphere?
The hydrosphere is the set of all the waters of the Earth. It represents about 67% of the total surface of our planet, that is, almost two thirds, so it could well have been called planet “Water”. The average depth of the oceans is 3.5 km. The account taken by the scientists is that salt water represents 97% of the total liquid vital, leaving only 3% for fresh water. This original disproportion gives us to understand why there are so many problems with water for human and animal consumption on our planet. Worse yet, more than 98% of the fresh water is frozen, leaving in theory only 0.06% for consumption. But in practice, this must be discounted contaminated and poisoned water that are not suitable for drinking. This is the great drama that the population lives in numerous places on Earth.