Permeable rock layers or sediments that transmit groundwater freely are called ____.

The term used for permeable rock layers or sediments that transmit groundwater freely is aquifers. Aquifers are geological formations that have the ability to store and transmit significant quantities of water, allowing for the movement of groundwater through the interconnected pores or fractures within the material. This property makes aquifers crucial for supplying water to wells and springs, making them vital resources for drinking water and agricultural irrigation.

In contrast, aquitards are layers that do not transmit water as freely, acting as barriers to groundwater flow. Springs refer to natural discharges of groundwater flowing to the surface, while caverns are underground chambers formed by the dissolution of rock, often associated with the presence of groundwater but not specifically defined by their ability to transmit water. This distinction illustrates why aquifers are fundamentally important in the hydrological cycle and resource management.