The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle, is known as?

• A. Plate Tectonics
• B. Deposition
• C. Weathering
• D. Dust Bowl

Answer: (A)

Plate tectonics explains the movement of Earth's lithospheric plates. The outer shell is divided into several rigid plates that float on the partly molten mantle beneath. Heat-driven convection currents in the mantle slowly move, pull, and push these plates, causing them to drift, collide, or slide past one another at their boundaries. This movement leads to phenomena like earthquakes, volcanoes, and the formation of mountains, and is supported by evidence such as matching shapes of coastlines, shared fossil records, and the pattern of magnetic stripes on the ocean floor. This term directly describes the mechanism described in the question. The other options don’t address the movement of large Earth-forming pieces: deposition is about laying down sediment, weathering is rock breakdown, and the Dust Bowl refers to an environmental disaster, not a geologic theory.