Afire requires oxygen to burn, and oxygen-enriched air is a fire hazard because the burning rate of combustible materials is increased. Given these facts, how do you increase the burn rate among the following options:
- an electric stove
 - exercise
 - burn wet materials
 - friction
 - add more oxygen
 - decrease amount of fuel
 - a hydraulic system
 - decrease the oxygen


 

     add more oxygen    