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.

[Q]: Fact: a hole over antarctica causes global warming. 
Question: What does a hole over Antarctica cause?
[A]: Global warming.


[Q]: Fact: Fossil fuels can be formed by layers of sediment pushing down on decomposing algae. 
Question: What is a product of layers of sediment pushing down on decomposing algae over time?
[A]: Fossil fuels.


[Q]: Fact: mammalian teeth are important for survival. 
Question: What is important for survival?
[A]:
Mammalian teeth.