You are presented with the question "Eyes are used by animals for seeing by sensing what?" and the following answer choices: 
- focusing a lens
 - an electron microscope
 - objects that have mass
 - chemical messengers
 - basic building blocks of life
 - electromagnetic waves
 - matter vibrating
 - rain or sun shine

Now knowing that eyes are used for seeing by animals by sensing light and visible and invisible light is energy in the form of electromagnetic waves, choose the best answer.


 

      electromagnetic waves   