What does the theory of plate tectonics primarily explain?

The theory of plate tectonics primarily explains the movement of Earth's lithosphere, which is the rigid outer layer of the Earth consisting of the crust and the uppermost part of the mantle. According to this theory, the lithosphere is divided into several large, rigid plates that float on the semi-fluid asthenosphere beneath them. These tectonic plates are constantly in motion, driven by forces such as mantle convection, slab pull, and ridge push.

The movement of these plates is responsible for many geologic phenomena, including earthquakes, volcanic activity, the formation of mountain ranges, and the creation of oceanic and continental features. This theory revolutionized our understanding of Earth's geologic processes and provided a comprehensive framework for explaining how and why these dynamic changes occur over geological time scales.

Understanding the motion of the lithosphere is crucial for interpreting various natural processes and hazards, making this choice the most accurate representation of what the theory of plate tectonics encompasses.