Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Reptiles typically reproduce sexually.

Answer: How do reptiles typically reproduce?

Question: Natural resource type of resource is limited in supply and cannot be replaced except over millions of years.

Answer: What type of resource is limited in supply and cannot be replaced except over millions of years?

Question: Group 16 is called the oxygen group.

Answer:
Group 16 is called what?