Which term describes the Earth's solid portion comprising the crust and outer mantle?

• A. Geosphere
• B. Atmosphere
• C. Hydrosphere
• D. Cryosphere

Answer: (A)

The solid part of Earth, including the crust and the mantle, is described by the geosphere. This term encompasses all the rocky and mineral portions of the planet, from the crust down through the mantle (and into the core, though the question focuses on the solid exterior). Since the crust and outer mantle are made of rock and exist as the solid foundation of the planet, they fall under the geosphere.

The other options refer to different Earth systems: the atmosphere is the gaseous envelope around Earth, the hydrosphere includes all water, and the cryosphere covers frozen water like ice and glaciers.