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: Lichens are not a single organism, but rather an example of a mutualism.

Answer: Lichens are not a single organism, but rather an example of a what?


Question: A bow wake is created when the wave source moves faster than the wave propagation speed.

Answer: What is created when the wave source moves faster than the wave propagation speed?


Question: Property to time kind of variation does a rate measure.

Answer:
What kind of variation does a rate measure?