question: What sentence would provide a factual answer to this question: "reptiles lay what?"

answer: reptiles lay eggs

question: What sentence would provide a factual answer to this question: "In a forest without anyone around, a fire may be started by"

answer: lightning can cause a forest fire

question: What sentence would provide a factual answer to this question: "Sedimentary rock may be a result of"

answer:
nearly all fossils are found in sedimentary rock