Fact 1: Acavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone.

Fact 2: Limestone caves are formed when acids attack and dissolve the calcite in limestone.

Given the two facts above, answer the question "what are caverns formed from?" with the following options: 
- storing water
 - streams
 - fossil fuels
 - limestone
 - streams.
 - Rocks
 - crust
 - mines


 

    limestone     