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: wiring requires metals. 
Question: What can you use in wiring to produce current?

Output: metals.


Input: Consider Input: Fact: Vertebrates have a complete digestive system and a closed circulatory system. 
Question: vertebrates have a complete digestive system and a what?

Output: closed circulatory system.


Input: Consider Input: Fact: Heating with coal can cause air pollution. 
Question: Heating with coal can cause?


Output: air pollution.