<span>C. Does eating less fat increase a mouse's lifespan?
(If a mouse eats less fat in its meals then will it live longer: compared to other mice lives.
</span>This is a testable question that can be answered by designing and conducting an experiment.
I think D could be correct as well.
My final answer is D.
When a red giant has insufficient mass it pretty much sheds its outer layer to leave the center core know as the white dwarf