instruction:
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: a doorbell converts  kinetic  energy into sound. 
Question: A doorbell converts _ into sound?
answer:
kinetic energy.


question:
Fact: Hummingbirds co-evolved with plants. 
Question: Hummingbirds are what they are today as a necessary consequence of their relationship to what?
answer:
Plants.


question:
Fact: Medicine is used for curing babies when they are sick. 
Question: Medicine is used for doing what to babies when they are sick?
answer:

curing them.