Study a place without actually having to be there.
Answer:
area of land dropping steeply towards deep ocean basins
"The lithosphere is subdivided into tectonic plates. The upper part of the lithosphere which chemically reacts to the atmosphere, hydrosphere and biosphere through the soil forming process is called the pedosphere. The lithosphere is underlain by the athenosphere which is the weaker, hotter, deeper part of the upper mantle."