Flexi Says: The hydrologic cycle or water cycle is one of the most important biogeochemical cycles on earth. The water cycle is responsible for the movement of water above and below the surface of the earth. It ensures the availability of water for aquatic organisms as well as land organisms. The water cycle also plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation occurs. If the water cycle stopped, then, air will be dry, there will be no water in lakes, rivers leading to the loss of vegetation which ultimately causes the death of organisms.