A cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone.
Underground caves and caverns pose an exciting adventure to many.
Underground caves can be formed by carbonic acid in groundwater seeping through rock and dissolving limestone.
What can be formed by carbonic acid in groundwater seeping through rock and dissolving limestone?

  water
  swamp vegetation
  Calcium carbonate
  sunlight
  contamination
  loose soil
  underground caves
  arsenic