Fact 1: Some precipitation that falls on land may soak into the ground, becoming groundwater.

Fact 2: Wells are usually used as a source for groundwater.

Given the two facts above, answer the question "What can be filled with precipitation that falls on land and soaks into the ground?" with the following options: 
- fields
 - Roads
 - rain
 - wells
 - nektar
 - porous
 - solutes
 - river


 

    wells     