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: many plants respond to the days growing shorter in September by going dormant. 
Question: when do plants respond to shorter days by going dormant?
answer:
September.


question:
Fact: blood traveling to the heart is deoxygenated. 
Question: Blood traveling to the heart is?
answer:
deoxygenated.


question:
Fact: Caves can be formed by carbonic acid in groundwater seeping through rock and dissolving limestone. 
Question: What is one element used to create caves?
answer:

carbonic acid.