initiation of nuclear fusion increase in noble gas destabilization increase in thermal energy initiation of photosynthesis reactions
I gave my students this multiple choice question: The compression of matter due to gravitational attraction increased as the protoplanets formed. What was a result of this compression within each protoplanet?

Only one answer is correct among these 4 choices:
- initiation of nuclear fusion
- increase in noble gas destabilization
- increase in thermal energy
- initiation of photosynthesis reactions

Could you tell me which one is correct?

increase in thermal energy