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: chemical weathering causes iron to turn brown, red, or orange. 
Question: What does chemical weather cause iron to do?
[A]: Change color to brown.


[Q]: Fact: Deep gorges are formed by flowing rivers through erosion over long periods of time. 
Question: What are formed by flowing rivers through erosion over long periods of time?
[A]: deep gorges.


[Q]: Fact: operating an automobile contributes to Global warming. 
Question: What contributes to global warming?
[A]:
operating an automobile.