What defines an Aquifer?

An aquifer is specifically defined as a geological formation that can yield usable water, typically accessed through wells or springs. This definition highlights two critical components: the geological structure that stores water and its ability to produce that water when required. Aquifers are essential to the water supply for many communities, as they store groundwater that can be tapped for drinking water, irrigation, and other uses.

The other choices do not accurately represent what an aquifer is. The first option speaks about soil's capacity to retain pollutants, which is unrelated to the characteristics of an aquifer. The third option refers to surface water reservoirs, which are different from aquifers because reservoirs store water on the surface rather than underground. The fourth option, mentioning a water treatment plant, pertains to a facility that processes water for safe consumption and does not concern the natural formations of groundwater resources. Therefore, the definition of an aquifer is clearly aligned with its role in providing access to usable water.