Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.

[EX Q]: Fact: Blowing air into a whistle causes air to move inside the whistle. 
Question: Blowing air into what causes air to move inside it?
[EX A]: whistle.

[EX Q]: Fact: dogs require nutrients to grow and heal. 
Question: what requires nutrients to grow and heal?
[EX A]: dogs.

[EX Q]: Fact: plasma ionizes metal. 
Question: what does plasma ionize?
[EX A]:
metal.