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: Burning fuel in furnaces can kill. 
Question: Burning fuel in a furnace can?
kill.

Fact: water flow through soil is variable. 
Question: What is the rate of water flow of soil?
variable.

Fact: seismic waves cause the ground to shake. 
Question: Seismic waves cause what to shake?

the ground.