You are presented with the question "what does hitting an object cause?" and the following answer choices: 
- frequency waves
 - harmful substances
 - Electrical energy
 - chemical reaction
 - friction
 - Movement
 - heat energy
 - chemical changes

Now knowing that hitting an object causes the particles in that object to vibrate and by it's nature, a vibration is a frequency wave , choose the best answer.


 

 frequency waves        