You are presented with the question "What acts as an aid to a car engine converting gasoline into motion and heat?" and the following answer choices: 
- Energy.
 - oxygen
 - nitrogen
 - helium
 - argon
 - energy
 - burning
 - sugar

Now knowing that acar engine usually converts gasoline into motion and heat through combustion and oxygen acts as an aid to combustion, choose the best answer.


 

  oxygen       