the heat from earth core results in the cycling of matter in the mantle through convection currents. the model shows four locations on earth labeled P-S and how the mantle circulates heat from the core to the crust. Which change is observed to the convention currents in the mantle? A. tectonic plates move. B. water circulates in the ocean. C. crust becomes hotter, raising the surface temperature. D. crust becomes more dense, sinking to form trenches.