You are presented with the quiz "a rainbow is formed by what into all different colors?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "arainbow is formed by refraction of light by separating light into all different colors" and "rainbows are an optical phenomena due to the diffraction of light waves". 

So, what's the best answer to the question?


 

  diffraction         