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.

Example Input: Fact: an animal requires food to grow and heal. 
Question: What does an animal require food for?
Example Output: to grow and heal.

Example Input: Fact: heat is detected by sensory nerve cells. 
Question: What is detected by sensory nerve cells?
Example Output: heat.

Example Input: Fact: Playing is a complex interaction shared by mammals and other animals. 
Question: What is a complex interaction shared by mammals and other animals?
Example Output:
playing.