You are presented with the quiz "Being buried under soil and mud changes what into coal in wetlands over time?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "being burried under soil and mud changes peat into coal through extreme heat and pressure in a swamp over a long period of time" and "well, a swamp is a type of wetland". 

So, what's the best answer to the question?


 

 peat          