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

Q: A mushroom is the fruiting body that occurs after two hyphae mate and form a mycelium with sporangia.

A: What is the fruiting body that occurs after two hyphae mate and form a mycelium with sporangia?
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Q: Oxygen is transferred through capillaries.

A: Which blood vessels is oxygen transferred through?
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Q: In living systems, diffusion of substances into and out of cells is mediated by the plasma membrane.

A:
In living systems, diffusion of substances into and out of cells is mediated by the what?
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