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.

Input: Consider Input: Fact: An object's shape can be changed by removing material. 
Question: What is one way an object's shape can be changed?

Output: removing material.


Input: Consider Input: Fact: Water must not be polluted to be safe. 
Question: What can happen to water to make it unsafe?

Output: Pollution.


Input: Consider Input: Fact: guitars make sound with vibration. 
Question: What do guitars make sound with?


Output: vibration.