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: molds have special structures for penetrating a host. 
Question: What has special structures for penetrating a host?

Answer: molds.


Question: Fact: x-rays are used in oncology. 
Question: what are used in oncology?

Answer: x-rays.


Question: Fact: A radio creates sound waves. 
Question: What creates sound waves?

Answer:
a radio.