question: What sentence would provide a factual answer to this question: "High carbon steel contains"

answer: ferrous metals contain iron

question: What sentence would provide a factual answer to this question: "A coal mine is what?"

answer: coal mine is a source of coal under the ground

question: What sentence would provide a factual answer to this question: "Sedimentary rock is where you'll find most"

answer:
nearly all fossils are found in sedimentary rock