Final answer:
The crust is the part of Earth that contains the highest mountains and deepest oceans. It is a thin, brittle outer shell and is part of the larger lithosphere, which includes the crust and the rigid upper part of the mantle.
Step-by-step explanation:
The part of Earth that contains the highest mountains and deepest oceans is the crust. The Earth's crust is a relatively thin, brittle outer shell made of rock, which is part of the larger lithosphere. The lithosphere includes the crust and the uppermost part of the mantle. Notably, the highest point on the Earth's crust is Mount Everest, and the deepest point within the oceans is located in a trench off the coast of the Philippines.
The mantle, below the crust, is a large part of the solid Earth that extends down to about 2900 kilometers and consists of more dense material. The mantle material can flow slowly due to the high temperatures and pressures. Above the mantle is the asthenosphere, a mechanically weaker region that helps the movement of tectonic plates located in the lithosphere above.
Differentiating between the crust and lithosphere is important because the crust alone is the surface layer where the extreme topographical features are present, whereas the lithosphere includes the rigid upper part of the mantle and plays a crucial role in plate tectonics and the movement of continents and ocean floors.