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.

Q: Fact: phones require electrical energy to function. 
Question: What do phones require to function?

A: electrical energy.
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Q: Fact: melting means changing from a solid into a liquid by increasing temperature. 
Question: what is increased to cause something to change from a solid into a liquid?

A: temperature.
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Q: Fact: thermal expansion can cause burns. 
Question: what can cause burns?

A:
thermal expansion.
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