Here's why:

* Zone of Saturation: This zone is the area below the Earth's surface where all the spaces between soil and rock particles are completely filled with water. This water is what we call groundwater.

* Water Table: The top of the zone of saturation is called the water table.

* Zone of Aeration: The area above the water table is called the zone of aeration. Here, the spaces between soil and rock particles are filled with air and some water.

Let me know if you have any more questions!