Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

[Q]: How much is involved in the reaction does the coefficient in front of an element in a formula indicate.
[A]: What does the coefficient in front of an element in a formula indicate?

[Q]: Simple carbohydrates can be classified in terms of chain length.
[A]: Which carbohydrates can be classified in terms of chain length?

[Q]: Insulin is made up of two polypeptide chains.
[A]:
Insulin is made up of how many polypeptide chains?