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: You call a substance that is not an acid or a base neutral.

Answer: What do you call a substance that is not an acid or a base?


Question: Are humans a new or old species on the earth?

Answer: Are humans a new or old species on the earth?


Question: A collapsing nebula leads to nuclear fusion process.

Answer:
A collapsing nebula leads to what process?