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: Coal is used to produce the movement of electrons by burning in coal-fire power stations. 
Question: Coal is used to produce the movement of electrons by what in coal-fire power stations?

Output: burning.


Input: Consider Input: Fact: Natural magnetism is used for pointing north in a surveying tool. 
Question: Who would use a tool that uses a magnet that points north?

Output: surveyor.


Input: Consider Input: Fact: starfish lack a centralized nervous system. 
Question: What lacks a centralized nervous system?


Output: starfish.