question: What sentence would provide a factual answer to this question: "Carbonic acid dissolves what to form caverns?"

answer: a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone

question: What sentence would provide a factual answer to this question: "If a new predator begins eating prey, what will happen to the preys population?"

answer: if a new predator begins eating prey then the population of that prey will decrease

question: What sentence would provide a factual answer to this question: "At the beach you are likely to find this type of stone:"

answer:
sedimentary rocks are formed from sediment compacting together