You are presented with the question "How do you increase the burn rate?" and the following answer choices: 
- an electric stove
 - exercise
 - burn wet materials
 - friction
 - add more oxygen
 - decrease amount of fuel
 - a hydraulic system
 - decrease the oxygen

Now knowing that afire requires oxygen to burn and oxygen-enriched air is a fire hazard because the burning rate of combustible materials is increased, choose the best answer.


 

     add more oxygen    