_____________________comes from plant remains after they had formed a layer of peat. 

________________ are materials that formed as ancient plants and animals decayed underground. 

Which of the following is NOT a fossil fuel?

________ is an unstable element removed from rocks mined underground. 

Fossil fuels are considered ___________ because they are limited.  

______________ is shipped under pressure and piped into homes for heating and cooking. 

What is the primary source of energy for coal formation? 

___________ is used to make gasoline and diesel.  

The formation of fossil fuels....