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

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

A: Lichens are not a single organism, but rather an example of a what?
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Q: The heterotroph eats only or mainly plants.

A: The heterotroph eats only or mainly what?
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Q: The brain is the most complex organ in the human body.

A:
What is the most complex organ in the human body?
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