ocean ridges- constructive plate boundaries, lava rises to form ridge, underwater volcanoes.
rift valleys- plates moving apart on continents, constructive plate boundary.
deep sea trenches- destructive plate boundary, oceanic and continetal crust moving towards eachother, oceanic crust will sink beneath oceanic plate- such as Mariana trench
island arc, oceanic crust melts and rises in plumes to form new land on the surface
fold mountains- destructive plate boundary, continental on continental, pushed upwards and forms mountain ranges.