Around two thirds of the human body is made up of water, with even bones containing 25% water. On average, humans need 2.4 liters of water per day to stay healthy. Water is able to dissolve many substances thanks to its molecular structure, but this also means that all water circulates through the environment in the water cycle, moving from rivers and clouds to faucets, glasses, and toilets. The document discusses the importance of water for the human body and its constant recycling through the water cycle.