Answer:
Earthquakes and volcanoes.
Step-by-step explanation:
Earthquakes and volcanoes are responsible for the movement of these continental and oceanic plates because movement of these tectonic plates occurs due to convection currents in the molten rock in Earth's mantle present below the crust. Earthquakes and volcanoes are the short-term results of these tectonic movement while the long-term result of these tectonics causes the movement of entire continents over millions of years. The density of crust is 2.2 g/cm3, the density of upper mantle is 3.4 g/cm3, the density of lower mantle is 4.4 g/cm3, the density of outer core is 9.9 g/cm3 and the density of inner core is 12.8 g/cm3