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: Hybridization model model helps explain molecules with double or triple bonds.

Answer: Which model helps explain molecules with double or triple bonds?


Question: Pleiotropic effects causes symptoms associated with sickle-cell disease.

Answer: What causes symptoms associated with sickle-cell disease?


Question: Blood enters the heart in atria valve.

Answer:
Blood enters the heart in what valve?