You are presented with the question "What are the affects of burning fuel on human health?" and the following answer choices: 
- emissions
 - They aid lung health.
 - direct damage to the lungs
 - They are a hazard.
 - The affects are mildly healthy
 - The fuel burns clean.
 - Greenhouse gases
 - Global warming

Now knowing that carbon monoxide is a gas produced by furnaces and other devices that burn fuel and carbon Monoxide Carbon monoxide is a health hazard, choose the best answer.


 

    They are a hazard.     