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.

[EX Q]: Fact: cattle can have a negative impact on the environment. 
Question: what can have a negative impact on the environment?
[EX A]: cattle.

[EX Q]: Fact: penguins are endothermic tetrapod vertebrates. 
Question: what are endothermic tetrapod vertebrates?
[EX A]: penguins.

[EX Q]: Fact: the liver helps reduce acidity of food entering from the highly acidic stomach. 
Question: what helps reduce acidity of food entering from the stomach?
[EX A]:
liver.