You are presented with the question "What causes earth quakes?" and the following answer choices: 
- electromagnetic energy
 - movement
 - harmful substances
 - the force
 - shaking
 - compressional forces
 - Water expanding
 - energy of moving objects

Now knowing that faulting of rock in Earth 's crust causes earthquakes and thrust faults are a result of compressional forces in the Earth's crust, choose the best answer.


 

      compressional forces   