question: What sentence would provide a factual answer to this question: "A source of heat could be"

answer: a radiator is a source of heat

question: What sentence would provide a factual answer to this question: "Which is a source of raw materials?"

answer: if something is a raw material then that something comes directly from a source

question: What sentence would provide a factual answer to this question: "When soil is disrupted to extreme levels"

answer:
erosion of soil has a negative impact on the environment