Final answer:
An aquifer layer is most likely made of cracked rocks, such as sandstones or fractured limestone, that allow water to flow through them.
Step-by-step explanation:
An aquifer layer is most likely made of cracked rocks. This layer is composed of permeable rocks, such as sandstones or fractured limestone, which allow water to flow through them. These rocks have cracks and crevices that hold water, forming underground reservoirs or channels that supply water to wells or springs.
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