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

Q: The refrigerator door contains iron of the following statements best explains why magnets usually stick to a refrigerator door.

A: Which of the following statements best explains why magnets usually stick to a refrigerator door?
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Q: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.

A: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?
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Q: Antartica continent is the only one that reptiles don't inhabit.

A:
Which continent is the only one that reptiles don't inhabit?
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