Final answer:
Earth doesn't run out of water on a global basis due to the water cycle, which replenishes the water supply. The water cycle involves the evaporation of water, condensation into clouds, and precipitation back to the Earth's surface. This continuous process ensures that there is always water available.
Step-by-step explanation:
Water is a limited resource on Earth, and it is used faster than it is replaced. However, Earth doesn't run out of water on a global basis due to the water cycle. The water cycle is a continuous process that involves the evaporation of water from bodies of water, condensation into clouds, and precipitation back to the Earth's surface. This cycle constantly replenishes the water supply, ensuring that there is always water available.
For example, when water evaporates from the ocean or lakes, it forms clouds. These clouds then release precipitation in the form of rain, snow, or hail, which replenishes freshwater sources like rivers, lakes, and underground aquifers. The water that is used by humans and other living organisms eventually goes back into the environment through excretion, sweating, or other processes, and then re-enters the water cycle.
The water cycle also helps distribute water around the globe. While some areas may experience water scarcity, other regions receive more precipitation and have abundant water resources. It is important to understand the water cycle and use water sustainably to ensure that future generations can access this vital resource.