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: In the tropics tradewinds are the prevailing winds called.

Answer: In the tropics what are the prevailing winds called?


Question: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.

Answer: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?


Question: Steppes is the term for dry climate regions at higher altitudes that have short grasses and low bushes.

Answer:
What is the term for dry climate regions at higher altitudes that have short grasses and low bushes?