Fact 1: Blowing air into a whistle causes air to vibrate inside the whistle.

Fact 2: Air, too, contains oxygen.

Given the two facts above, answer the question "If you blow oxygen inside of a whistle, what will vibrate inside of the whistle?" with the following options: 
- an object
 - friction
 - energy
 - waves
 - heat
 - oxygen
 - a chime
 - sound


 

      oxygen   