You are presented with the question "What is used for generating heat by burning?" and the following answer choices: 
- compacted dead plants
 - basic building blocks of life
 - deoxyribonucleic acid
 - igniting fuel and oxidiser
 - hard plastics
 - soft styrofoam
 - Sulfur dioxide
 - thin metal sheets

Now knowing that coal is used for generating heat by burning and coal forms from dead plants, compacted, choose the best answer.


 

 compacted dead plants        