You are presented with the question "what has its soil and mud changed by extreme heat over long periods of time?" and the following answer choices: 
- elms
 - bogs
 - bamboo
 - earth
 - deltas
 - coal
 - corn
 - swea

Now knowing that being burried under soil and mud changes vegetation into peat through extreme heat and pressure in a swamp over a long period of time and bogs are characterized by cushion-like vegetation and an accumulation of peat, choose the best answer.


 

  bogs       