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

Q: An acorn growing into an adult tree will take the longest time to observe.

A: Which of these will take the LONGEST time to observe?
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Q: If an air mass forms over an ocean it is called a maritime air mass.

A: If an air mass forms over an ocean it is called what type of air mass?
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Q: Pyramids of net production and biomass reflect low level of efficiency.

A:
Pyramids of net production and biomass reflect what level of efficiency?
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