In this task, you are given a question and a corresponding answer. Your task is to generate a fact statement that is useful in answering the given question.

Question: Geese fly south for the winter because? Answer: of instinct.
migration is an instinctive behavior

Question: What are some of the risks of using fertilizer? Answer: Damaging the planet.
fertilizers are a source of pollution

Question: Why are ferrous metals magnetic? Answer: The iron contained inside of them.

ferrous metals contain iron