question: What sentence would provide a factual answer to this question: "March in the northern hemisphere is what in the southern hemisphere?"

answer: winter in the Northern Hemisphere is during the summer in the Southern Hemisphere

question: What sentence would provide a factual answer to this question: "Dead organisms are the source of what for decomposers?"

answer: dead organisms are the source of nutrients for decomposers

question: What sentence would provide a factual answer to this question: "Which is the likeliest part of a pencil to have been mined?"

answer:
pencil lead contains mineral graphite