Which theory states that Earth's lithosphere is broken up into large plates that move and rejoin?

• A. Pollution
• B. Urbanization
• C. Plate Tectonic Theory
• D. Desertification

Answer: (C)

Movement of Earth’s outer shell is explained by Plate Tectonic Theory. The lithosphere is broken into large plates that ride on the partially molten layer beneath and slowly move due to convection in the mantle. Where these plates interact at their edges, they can pull apart, collide, slide past one another, or subduct, leading to the creation of new crust, mountains, earthquakes, and volcanoes. This description—plates moving and rejoining—sits at the heart of Plate Tectonic Theory, which also ties together the ideas of continental drift and seafloor spreading. The other options describe human or environmental processes like pollution, urban development, or desertification, not the geologic dynamics of Earth’s crust.