Fact 1: If soil is permeable then water easily flows through that soil.

Fact 2: H2O is the scientific name for water.

Given the two facts above, answer the question "what flows with ease through soil if it's permeable?" with the following options: 
- mulch
 - wind
 - NaCl
 - CO 2
 - h2o
 - oxygen
 - vapor
 - H20


 

     h2o    