The rock which has the capacity to retain underground water is?

Answer Details

Underground water (groundwater) is stored within rocks in a zone called the zone of saturation. For a rock to retain underground water, it must have interconnected pore spaces, fractures, or gaps between its grains that allow water to seep in and be held. This property is called permeability.

A permeable rock allows water to pass into and through it because its pores or cracks are connected. Rocks such as sandstone and chalk are permeable and can act as aquifers, storing large volumes of groundwater.

A compact rock has tightly packed grains with minimal pore space, so it cannot absorb or store significant water. A crystalline rock (such as granite) has an interlocking crystal structure with very few connected pores, making it a poor water store. An impermeable rock actively prevents water from passing through it at all, meaning water runs off its surface rather than being retained within it.

The correct answer is permeable, because only a rock with connected pore spaces can absorb, hold, and transmit underground water.