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.

Input: Consider Input: Fact: a flashlight requires a source of energy to produce light. 
Question: What requires a source of energy to produce light?

Output: flashlights.


Input: Consider Input: Fact: Roots have parts that regenerate after bisection. 
Question: What have parts that regenerate after bisection?

Output: roots.


Input: Consider Input: Fact: ferns use stems to store water. 
Question: What uses stems to store water?


Output: ferns.