a). Something with a head, thorax, and abdomen;
b). chemical messengers;
c). flow of electrons;
d). Electrical energy;
e). Faulting of rocks in the crust;
f). solid, liquid, gas;
g). electromagnetic energy;
h). that material's properties;

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, the origin of P-waves and S-waves can be traced back to what?
Answer:
e).