If earth was completely solid and homogeneous throughout, how would have the P and S waves behave when they traveled through it? Explain while giving reference to how they actually behave.

The current status of the two body waves- P and S are as follows. The P waves are the fastest seismic waves and can travel through all materials, whereas the S waves are somewhat slower and can travel through only solids. The P waves are compressional whereas the S waves are shear.
However, if the earth was completely solid and homogenous throughout, there would be completely a different scenario. The P and the S waves would travel in straight paths. But due to heterogeneity of the earth, there is the possibility of refraction taking place and the seismic waves take a curvy path. Also, observed are the various discontinuities which take place due to changes in earth’s material and properties.