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: 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: Origami causes an object to change shape. 
Question: What is a method for changing an object's shape?
answer:
origami.


question:
Fact: Limestone caves are formed by depositions. 
Question: How are limestone caves formed?
answer:

Depositions.