What two layers make up the lithosphere?

The lithosphere is composed of two distinct layers: the crust and the uppermost portion of the mantle. This combination is crucial for understanding the Earth's structure and geological processes. The crust is the outermost layer of the Earth, consisting of solid rock, while the upper mantle lies just beneath the crust and is also composed of solid rock, albeit at a higher temperature and pressure. Together, these two layers form the lithosphere, which is rigid and extends from the surface down to a depth of about 100 kilometers.

The other choices involve different layers of the Earth that do not combine to form the lithosphere. For instance, the core consists of both a liquid outer core and a solid inner core, which are not part of the lithosphere. The mantle, although it includes part of the lithosphere, by itself does not define this term without the inclusion of the crust. Understanding these layers is fundamental for studying geological phenomena such as plate tectonics and earthquakes.