Fact 1: Being burried under soil and mud changes vegetation into peat through extreme heat and pressure in a swamp over a long period of time.

Fact 2: Bogs are characterized by cushion-like vegetation and an accumulation of peat.

Given the two facts above, answer the question "what has its soil and mud changed by extreme heat over long periods of time?" with the following options: 
- elms
 - bogs
 - bamboo
 - earth
 - deltas
 - coal
 - corn
 - swea


 

  bogs       