Final answer:
The zone of saturation is known as the phreatic zone, where rock and soil pore spaces are completely filled with water, beneath the water table.
Step-by-step explanation:
The zone of saturation is also known as the phreatic zone. In this layer, the pore spaces of rocks and soil are completely filled with water, differentiating it from the vadose zone, where pore spaces contain mostly air. The water table delineates the boundary between these two zones — above it lies the unsaturated (vadose) zone, and below it lies the saturated (phreatic) zone. It's essential to understand the concepts of porosity and permeability, which influence the storage and movement of groundwater within these zones. Porosity is a measure of the void spaces in a material and is crucial for determining how much water a rock or soil can hold. Permeability refers to the ability of a rock or soil to transmit water through its pores.