Answer:
The theory of plate tectonics proposes that the Earth's outer layer, or lithosphere, is broken up into a number of large plates that interact with one another. These plates are slowly moving across the Earth's surface, driven by convection currents in the mantle below.
The mantle is the layer of the Earth that lies beneath the crust, and it is made up of hot and viscous rock. At certain depths, the mantle rock can become partially molten, and this creates convection currents. These currents are driven by the heat difference between the deeper, hotter parts of the mantle and the cooler, shallower regions.
As these convection currents move, they push against the base of the lithosphere, which is divided into several plates. The interaction between these plates creates a variety of geological features, including mountain ranges, volcanoes, and earthquakes.
The movement of the plates is hardly noticeable in human terms, with rates of movement averaging to just a few centimeters per year. However, over millions of years, these small movements can add up, leading to significant changes in the Earth's geography and climate. For example, the collision of two plates can result in the formation of a mountain range, while the separation of two plates can create a new ocean basin.