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: Bacteria in soil coverts atmospheric nitrogen into a form usable by flowers. 
Question: What converts nitrogen for flowers?
answer:
bacteria.


question:
Fact: Vertebrates are all chordates that have a spinal column. 
Question: What do all vertebrates have that invertebrates don't?
answer:
a spinal column.


question:
Fact: ink is used for hiding from predators by squids. 
Question: What is used for hiding from predators by squids?
answer:

ink.