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: A penguin must do increase muscle mass before molting.

Answer: A penguin must do what before molting?


Question: Landslides moving loose rocks downhill process is the best example of a sudden change to earth’s surface.

Answer: Which process is the best example of a sudden change to Earth’s surface?


Question: Mucous does the esophagus produce for lubrication.

Answer:
What does the esophagus produce for lubrication?