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: a flashlight requires a source of energy to produce light. 
Question: What requires a source of energy to produce light?
[A]: flashlights.


[Q]: Fact: wind causes wearing away of rock. 
Question: Wind can cause?
[A]: the wearing away of rock.


[Q]: Fact: Heat and pressure on skin can cause feelings of pain. 
Question: What can cause feelings of pain on the skin?
[A]:
heat and pressure.