First, the theory of plate tectonics is supported by the evidence of plate tectonics like mountain building. plate tectonics are huge rocks under the earths surface that move. And when they move and collide and cause lots of damage. Mountains rise because earths movement or also called plate tectonics. Plate tectonics are moving and colliding. The movement of plate tectonics don't just make mountains larger, plate tectonics also create ocean trenches and continental drift.