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

Answer: Which of the following statements best explains why magnets usually stick to a refrigerator door?

Question: Solid form do alkali metals take at room temperature.

Answer: What form do alkali metals take at room temperature?

Question: The cell wall acts as an extra layer of protection, helps the cell maintain its shape, and prevents dehydration.

Answer:
The cell wall acts as an extra layer of protection, helps the cell maintain its shape, and prevents what?