instruction:
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.
question:
Fact: skin is cooled by evaporation. 
Question: What cools the skin?
answer:
evaporation.


question:
Fact: Sight is the ability to see when light allows an image to be focused on the retina. 
Question: What is it called when light allows an image to be focused on the retina?
answer:
Sight.


question:
Fact: x-rays are used in diagnostics. 
Question: X-rays are used in?
answer:

diagnostics.