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

Output: a spinal column.


Input: Consider Input: Fact: DNA strands are called a polynucleotide. 
Question: What is a DNA strand?

Output: Polynucleotide.


Input: Consider Input: Fact: A ship is a form of water transportation. 
Question: A ship is an example of what?


Output: Water transportation.