This theory explains the movement of Earth's continents because the tectonic plates carry the continents as they slowly drift apart, collide, or slide past each other. For example, continents move away from each other at divergent boundaries where new crust forms, and they collide at convergent boundaries causing mountain building or subduction where one plate sinks beneath another. This movement over millions of years accounts for the shifting positions of continents, the formation of mountains, earthquakes, and volcanoes along plate boundaries.In summary, plate tectonics describes how Earth's lithosphere is broken into plates that move on the underlying mantle, driving the movement of continents and shaping Earth's surface features.