Answer:
c
Step-by-step explanation:
because as the magma cools and solidifies, the convection currents will stop and the Earth will become geologically dead.
Convection currents within the Earth's mantle are caused by hot material rising upwards, cooling, then dropping back toward the core. These currents are thought to be the driving force for tectonic plate activity in the crust. The moving magma in the mantle carries the plates floating on top of it.