Which of the following best describes an aquifer?

An aquifer is best described as a geologic formation that has the capacity to supply groundwater. This means it consists of porous rock or sediment that can store and transmit water, allowing it to be accessed through wells or springs. Aquifers play a crucial role in the hydrological cycle and are vital sources of freshwater for drinking, irrigation, and industrial use.

When considering the other options, a polluted water source does not accurately capture the definition of an aquifer; it highlights the condition of water rather than the geological characteristics needed for groundwater availability. A man-made water storage system refers to reservoirs or tanks designed for storing water, which is not how aquifers are formed. Additionally, a surface water body, such as lakes or rivers, is distinct from an aquifer, which is located beneath the earth's surface and involves groundwater rather than surface water. Understanding these distinctions reinforces the definition of an aquifer and its significance in water supply and management.