Final answer:
The majority of Earth's freshwater is contained in glaciers and ice caps, accounting for the largest reservoirs of fresh water, but groundwater serves as the largest source of usable freshwater.
Step-by-step explanation:
The majority of freshwater on Earth is contained in glaciers and ice caps. While oceans hold about 97% of Earth's water, it is not usable freshwater because it's too saline.
Freshwater is found predominantly in the form of ice in polar regions and Greenland, representing the largest freshwater reservoirs. Despite freshwater's abundance in these icy reservoirs, it remains largely inaccessible for direct human use.
Instead, shallow groundwater represents the largest source of usable freshwater. Although rivers and lakes are commonly used water sources, they only make up a small amount of the world's total water supply.
The complete question is: the majority of freshwater, whether accessible to humans or not, is contained in what reservoir? is: