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: phones require electrical energy to function. 
Question: What do phones require to function?
[EX A]: electrical energy.

[EX Q]: Fact: ecosystems use sunlight for growth. 
Question: What do ecosystems use sunlight for?
[EX A]: growth.

[EX Q]: Fact: being buried under soil and mud changes bogs through extreme heat over a long period of time. 
Question: what has its soil and mud changed by extreme heat over long periods of time?
[EX A]:
bogs.