How do increased understanding of the hydrosphere, watersheds and human uses of water support the phrase, "water is life? '

The cycle of water is called the hydrosphere. In this cycle, the evapotranspiration of water forms the clouds in the atmosphere whose rain waters the earth’s watersheds. It is from watersheds that all living organisms draw their water from to live. Negative interruption of this cycle leads famine and death. Therefore essentially ‘water if life’.

what subject is this