You are presented with the quiz "Shifting in the Earth's crust are caused by what?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "faulting of rock in Earth 's crust causes earthquakes" and "earthquakes and volcanoes are violent proof of Earth's shifting crust". 

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


 

     fault in rocks      