You are presented with the question "what does dropping an object into water cause?" and the following answer choices: 
- oxygen
 - chemical changes
 - kinetic energy
 - radiation
 - freezing
 - activation energy
 - frequency waves
 - heat energy

Now knowing that dropping an object into water causes vibrations in the water and by it's nature, a vibration is a frequency wave , choose the best answer.


 

       frequency waves  