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

Q: The majority of arthropods live on land.

A: Where do the majority of arthropods live?
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Q: Atp or adenozine triphosphate is used for most energy functions in organisms.

A: What molecule is used for most energy functions in organisms?
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Q: The main advantage of urea is its very low toxicity.

A:
The main advantage of urea is its very low what?
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