The primary function of aquifers in the hydrological cycle is to store and transmit groundwater, which is crucial for supplying freshwater to ecosystems, agriculture, and human consumption. Aquifers form through the infiltration of rainwater through permeable rock layers and act as vital reservoirs. They help regulate and maintain water tables and can determine the flow direction of surface water. Additionally, aquifers can sustain rivers and wetlands by providing base flow, thus playing a crucial role in maintaining overall hydrological balance while supporting various life forms.