Answer:

• Why do you think S-waves cannot penetrate or pass through the inner core even though they are solid?

S-waves move in an up and down motion perpendicular to the direction of wave travel. This produces a change in shape for the Earth materials they move through. Only solids resist a change in shape, so S-waves are only able to propagate through solids.

• How did scientists conclude the composition of the layers of the Earth?​

Scientists use waves to study the different layers of the earth. Usually, they use seismic waves, which are waves generated by earthquakes or nuclear-test explosions. ... So, scientists study the path and speed of these waves through the earth to decipher boundaries and the materials that make up the layers.