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: One function of the gallbladder is to reduce the acidity of food. 
Question: What is one function of the gallbladder?
answer:
reduce acidity of food.


question:
Fact: expansion can cause fatigue. 
Question: what can cause fatigue?
answer:
expansion.


question:
Fact: Nematodes reproduce sexually. 
Question: Which reproduce sexually?
answer:

Nematodes.