Answer:
1. Primary or P waves are push and pull waves
2. Secondary, S or Shear Waves are also called transverse wave
3. L or surface waves reach the earth's surface after P and S waves
Because if they were in the inside, then they would not be able to sexually reproduct and could not have offspring.
Inertia is what keeps everything moving, so if it didn't exist, the balls wouldn't keep going when they are kicked, or thrown.
