You are presented with the question "If you blow oxygen inside of a whistle, what will vibrate inside of the whistle?" and the following answer choices: 
- an object
 - friction
 - energy
 - waves
 - heat
 - oxygen
 - a chime
 - sound

Now knowing that blowing air into a whistle causes air to vibrate inside the whistle and air, too, contains oxygen, choose the best answer.


 

      oxygen   