question: What sentence would provide a factual answer to this question: "What usually occurs over a period of many years?"

answer: weathering usually occurs over a period of many years

question: What sentence would provide a factual answer to this question: "migration is when what move to different locations in an annual cycle?"

answer: migration is when animals move to different locations in an annual cycle

question: What sentence would provide a factual answer to this question: "humans will have to flee if their home is"

answer:
shelter can protect humans from weather