molten rock flowing in the asthenosphere convection cells in the lower mantle turbulence in the liquid outer core radioactive decay in the solid inner core
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: The magnetic poles of Earth frequently change location. What is the direct cause of this change in magnetic pole location?
Possibilities:
- molten rock flowing in the asthenosphere
- convection cells in the lower mantle
- turbulence in the liquid outer core
- radioactive decay in the solid inner core

turbulence in the liquid outer core