question: Along with potassium-40 and uranium , the decay of what element is a primary heat source driving plate tectonics ?
answer: thorium
turker_answer: Along with potassium-40 and uranium , the decay of thorium is a primary heat source driving plate tectonics .
rule-based: Along with potassium-40 and uranium , the decay a primary heat is source driving plate tectonics of thorium .