Answer:
Groundwater
Step-by-step explanation:
Although the total volume of water on Earth is 1,386 million km3, 97.5% of this total consists of oceans, seas and salt water lakes. In the part formed by freshwater, more than 2/3 are in the polar ice caps and glaciers, inaccessible for human use by current technological means. However 1/5 of the total freshwater supply in the world is in groundwater. Groundwater is the portion of water that remains underground, where it flows slowly until it discharges into surface water bodies, is intercepted by plant roots or extracted into wells.