question: What sentence would provide a factual answer to this question: "Thermal conduction is when materials conduct what through those materials?"

answer: thermal conduction is when materials conduct heat through those materials

question: What sentence would provide a factual answer to this question: "to determine how firm a certain mineral may be a person can:"

answer: quartz scratches glass easily

question: What sentence would provide a factual answer to this question: "What causes objects that have mass to be pulled down?"

answer:
gravitational force causes objects that have mass to be pulled down on a planet