Here's why:
* Plate Tectonics: The Earth's outer layer, called the lithosphere, is made up of large plates that move slowly over the mantle. This movement is driven by convection currents in the mantle, which is a hot, viscous layer beneath the crust.
* Continental Drift: The movement of these plates is responsible for continental drift, the gradual shifting of continents over millions of years.
* Earthquakes and Volcanoes: Plate movements cause earthquakes when plates collide or slide past each other, and volcanic eruptions when plates pull apart or one plate subducts beneath another.
Therefore, the crust is not stationary but is constantly in motion, shaping the Earth's surface and causing various geological phenomena.
