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: locusts spread disease and destroy crops. 
Question: What spreads disease and destroy crops?

Answer: locusts.


Question: Fact: erosion forms canyons. 
Question: What are formed by erosion?

Answer: canyons.


Question: Fact: Evolution occurs in animals as they respond to change in their habitat. 
Question: What occurs in animals as they respond to changes in their habitat?

Answer:
evolution.