Correct Response: A. Earthquakes generate P waves (compressional waves), S waves (shear waves), and surface waves. S waves penetrate Earth's crust and mantle, however S waves do not travel through liquids so they do not penetrate the liquid outer core. Seismologists examining seismic data collected from major earthquakes noticed a shadow zone where S waves were absent on the opposite side of the planet from where the seismic waves were generated. This led to the conclusion that the outer core was liquid. Although P and S waves are reflected differently from solids (B), this difference does not provide information on the physical character of the outer core. P waves can pass through high-temperature materials (C) and while P and S waves are refracted at different angles from irregular surfaces (D), this fact does not provide evidence of the liquid character of the outer core.
