Final answer:
An aquifer is a saturated, porous, and permeable sediment or rock layer below the water table (option C) that stores groundwater. Permeability and porosity are key characteristics of aquifers, with sedimentary rocks like sandstone and limestone often serving as excellent aquifers due to their ability to let water flow through them.
Step-by-step explanation:
An aquifer is defined as C. A saturated, porous, and permeable sediment or rock layer below the water table. Aquifers are essential underground reservoirs that store groundwater. Permeability is a critical feature of aquifers and refers to the ability of a rock or sediment to allow fluids to pass through it. This characteristic depends on both the porosity of the material (the volume of open space within the rock) and the interconnectivity of these spaces. Sedimentary rocks like sandstone and limestone, known for their high porosity and permeability, make excellent aquifers.
Groundwater within these aquifers moves slowly, seeping from one space to another and is a significant source of fresh water, often utilized for drinking and irrigation. Impermeable layers such as un-fractured igneous or metamorphic rock, or sedimentary rocks like shale, act as barriers to water flow and are known as confining layers.