Water Nuggets Practice Exam

The primary source of freshwater on Earth is glaciers and ice caps. This answer is supported by the fact that a significant portion of the Earth's freshwater is stored in the form of ice, predominantly in Antarctica and Greenland. Glaciers and ice caps collectively hold about 68.7% of the world's freshwater.

Rivers and lakes, while important sources of freshwater for ecosystems and human use, account for only a small fraction of the total freshwater available on Earth. Rainwater is a key component of the water cycle and contributes to freshwater availability, but it is ephemeral and relies on the precipitation process, making it less of a stable source compared to the vast reserves locked in ice. Desalinated water, while increasingly utilized for drinking and irrigation in arid regions, is not a natural source of freshwater, as it involves the expensive and energy-consuming process of removing salt from seawater.