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

Q: Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos.

A: Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as what?
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Q: Pangaea began breaking apart 250 million years ago.

A: How many millions of years ago did pangaea begin breaking apart?
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Q: Secondary alcohol forms a ketone when oxidized.

A:
What forms a ketone when oxidized?
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