Plate Margins
			q Interactions between plates occur along their edges. There are three types of plate margins: (1) Divergent margins        form mid-ocean ridges (over oceans) and rift valleys (over lands) (2)  Convergent margins        form deep-sea trenches (two oceanic plates or ocean+continental plates) or high mountains (such as Tibetan Plateau) (two continental plates). (3) Transform fault margins        form earthquake faults