Which layer of the Earth is described as the solid inorganic portion?

• A. Atmosphere
• B. Hydrosphere
• C. Biosphere
• D. Lithosphere

Answer: (D)

The layer of the Earth described as the solid inorganic portion is the lithosphere. This term encompasses the rigid outer layer of the Earth, which includes the crust and the uppermost part of the mantle. The lithosphere is essential because it comprises the solid materials that make up the Earth's surface, including rocks, soil, and minerals. This layer plays a crucial role in the geological processes that shapes the Earth's landscape, such as plate tectonics, erosion, and the formation of mountains.

The atmosphere, which is the layer of gases surrounding the Earth, and the hydrosphere, which includes all of the Earth's water in various forms, do not fit the description of a solid inorganic portion. The biosphere refers to all living organisms and their interactions with the ecosystems, which also does not pertain to the inorganic solid components of the Earth. Therefore, the lithosphere is the correct answer as it specifically denotes the Earth's solid inorganic layer.