You are presented with the question "what are formed by carbonic acid in groundwater seeping through rock dissolving limestone" and the following answer choices: 
- oceans
 - Calcium carbonate
 - coral reefs
 - enormous rooms
 - a solute
 - creeks
 - Greenhouse gasses
 - a hydraulic system

Now knowing that acavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone and caverns are characterized by enormous rooms, choose the best answer.


 

    enormous rooms     