Fact 1: Faulting of rock in Earth 's crust causes earthquakes.

Fact 2: Earthquakes generate P waves and S waves which can travel throughout the earth.

Given the two facts above, answer the question "The origin of P-waves and S-waves can be traced back to what?" with the following options: 
- Something with a head, thorax, and abdomen
 - chemical messengers
 - flow of electrons
 - Electrical energy
 - Faulting of rocks in the crust
 - solid, liquid, gas
 - electromagnetic energy
 - that material's properties


 

     Faulting of rocks in the crust    