What happens during infiltration

Infiltration is the process by which water on the ground surface enters the soil.

Explanation:

Infiltration is governed by two forces, gravity, and capillary action. While smaller pores offer greater resistance to gravity, very small pores pull water through capillary action in addition to and even against the force of gravity.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."