Which of the following best describes what an aquifer is? a. an unsaturated, losing stream bed or stratum below a spring.
b. the porous and permeable, saturated cone of depression in an aquitard. c. a saturated, porous and permeable layer or stratum. d. a layer or stratum in which groundwater flows downward to the water table.

The statement "a saturated, porous, and permeable layer or stratum" best describes the aquifer.

An aquifer is a liquid layer of porous rock, rock fractures, or uncemented equipment near the ground. A well can be used to extract groundwater from aquifers. Hydrogeology is the study of aquifer water flow and characterization.

Therefore, the correct option is c.

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b. the porous and permeable, saturated cone of depression in an aquitard.

Explanation:

An aquifer is an underground layer of water, surrounded by a porous, and saturated layer of water bearing rock. The aquifer is lined by a layer of bed of low permeability along its length. This layer is called an aquitard, and it usually forms a depression.