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.

Fact: Creating paper can lead to deforestation. 
Question: What can cause deforestation?
Creating paper.

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

Fact: Competition may cause lions to fight other lions. 
Question: What may cause lions to fight other lions?

competition.