Fact 1: Fanning a fire increases the oxygen near the fire.

Fact 2: Then nothing was heard but the bellows which fanned the fire of the furnace.

Given the two facts above, answer the question "Using a bellows can do what to the oxygen near a fire? " with the following options: 
- increase
 - evaporation
 - diminish
 - absorb
 - decrease
 - It expands
 - electrically
 - heat


 

 increase        