You are presented with the question "Which of the following added to groundwater creates caverns?" and the following answer choices: 
- a solute
 - permineralization
 - calcite
 - storing water
 - flooding
 - salinity
 - carbon dioxide
 - heating liquids

Now knowing that acavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone and any time water and carbon dioxide mix, carbonic acid is the result, choose the best answer.


 

       carbon dioxide  