The three main examples of constructive forces are crustal deformation, volcanic eruptions and deposition of sediment. Constructive forces are the processes that build land formations. These formations include mountains and sedimentary rock layers.
Crustal deformation refers to changes in the shape of the land, typically as a result of collisions between the Earth's plates. Volcanic eruptions are openings in the Earth's crust that allow for the release of molten rock. This rock, called "lava," turns into landforms of igneous rock after cooling. Deposition of sediment is the process in which loose particles are compacted into hard layers of sedimentary rock.