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

Q: Mechanical waves term describes waves that travel through matter.

A: What term describes waves that travel through matter?
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Q: The sun is considered the center of the solar system.

A: What is considered the center of the solar system?
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Q: Late adulthood begins in the mid-60s and continues until?

A:
Late adulthood begins in the mid-60s and continues until?
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