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

Fact 2: Well, a swamp is a type of wetland.

Given the two facts above, answer the question "Being buried under soil and mud changes what into coal in wetlands over time?" with the following options: 
- peat
 - phytoplankton
 - fields
 - oil
 - air
 - pH
 - sunlight
 - elms


 

 peat        