What is an aquifer?

An aquifer is defined as an underground layer of permeable rock or sediment that can store and transmit significant amounts of water. This characteristic makes aquifers crucial for supplying drinking water and irrigation throughout many regions. The ability of an aquifer to both hold and allow the passage of water enables wells and springs to tap into this resource.

When considering the other options, a layer of impermeable rock does not facilitate water movement, which is essential for the function of an aquifer. A surface water body refers to lakes, rivers, and other bodies of water above ground, which are distinct from the subsurface nature of aquifers. Lastly, vegetation near water bodies does not pertain to the geological definition or function of aquifers. Thus, the choice that accurately describes an aquifer is the one that highlights its ability to store and transmit water underground.