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: The sun is considered the center of the solar system.

Answer: What is considered the center of the solar system?


Question: 10 million years long can a large star be on the main sequence stage.

Answer: How long can a large star be on the main sequence stage?


Question: Heart disease is the leading cause of death in the united states.

Answer:
What is the leading cause of death in the united states?