question: What sentence would provide a factual answer to this question: "Making a pie produces a"

answer: cooking causes a chemical reaction

question: What sentence would provide a factual answer to this question: "Fogged up glass on a store window is a stage in the"

answer: condensation is a stage in the water cycle process

question: What sentence would provide a factual answer to this question: "Lightening could be a combustion of"

answer:
lightning can cause a forest fire