NES Elementary Education Subtest 2 Practice Exam

The three main layers of the Earth's geosphere are the crust, mantle, and core. The crust is the outermost layer, where we find landforms and bodies of water; it is thin compared to the other layers. Beneath the crust lies the mantle, which is composed of solid rock that flows slowly over geological timescales, enabling the movement of tectonic plates. The core is the innermost layer, made primarily of iron and nickel, and it is further divided into a solid inner core and a liquid outer core. Together, these three layers make up the geosphere, which is crucial for understanding geological processes and the structure of the Earth itself.

The other options refer to components that do not accurately represent the main layers of the geosphere. For instance, the ocean is not a layer of the Earth, but rather a body of water that interacts with the crust. Similarly, while the atmosphere, lithosphere, and hydrosphere are important aspects of Earth's systems, they represent different concepts rather than layers of the geosphere itself.