question: What sentence would provide a factual answer to this question: "Which would one most likely run into when crossing a stream?"

answer: aquatic animals live in bodies of water

question: What sentence would provide a factual answer to this question: "Ducks might their webbed appendages to"

answer: webbed feet are used for moving faster through water by aquatic animals

question: What sentence would provide a factual answer to this question: "Which rock is a fingernail harder than?"

answer:
measuring the hardness of minerals requires scratching those materials