Answer:
Crust sitting on top of molten rock of the mantle
Explanation:
Earth's crust is the geological name for what we usually call the surface of the planet, and it is immediately above the molten rock of the mantle, the next layer of the planet.
The crust happens to be fragmented in large pieces or tectonic plates, that can be seen as "drifting" on the mantle's molten rock, also known as magma.
In some areas tectonic plates are drifting away, allowing magma to reach the surface (volcanoes for example), or the seabed (forming mid-oceans crests).
In other areas tectonic plates are crashing each other, causing earthquakes, tidal waves, mountain formation and other relevant geological events.
