What defines the saturated zone in terms of water content?

The saturated zone is defined as the area below the water table where all the available spaces within the soil or rock are completely filled with water. This means that there is no air present in the pore spaces; they are fully occupied by water. The saturation of this zone is critical for various hydrological processes, as it influences groundwater movement and the availability of water resources.

In contrast, the options suggesting dryness or air content, such as being always dry or containing mostly air, do not accurately describe the characteristics of the saturated zone. Additionally, being above the water table refers to the unsaturated zone, where soil and rock may contain both air and water in their pore spaces. Understanding these distinctions is essential for comprehending groundwater behavior and management.