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: vein deposits of gold and silver are formed by granite. 
Question: what are vein deposits of gold and silver formed by?

Answer: granite.


Question: Fact: Flowers detect light and darkness. 
Question: What grows after detecting light?

Answer: Flowers.


Question: Fact: muscle contracting causes a person 's elbow to straighten. 
Question: muscle what causes a person 's elbow to straighten?

Answer:
contracting.