Answer:
1.crust,mantle,outer core,inner core.
2.outer core.
3.crust.
4.solid,liquid,gas.
5.solid.
6.The inner core is solid, the outer core is liquid, and the mantle is solid/plastic.
7.A seismic shadow zone is an area of the Earth's surface where seismographs can only barely detect an earthquake after its seismic waves have passed through the Earth. When an earthquake occurs, seismic waves radiate out spherically from the earthquake's focus.
8.Seismologists use seismic waves to learn about earthquakes and also to learn about the Earth's interior. ... Seismic waves travel outward in all directions from where the ground breaks and are picked up by seismographs around the world.geologists also use an indirect method. But instead of knocking on walls, they use seismic waves. When earthquakes occur they produce seismic waves. Geologists record the seismic waves and study how they travel through Earth.