Given a scientific question, generate a correct answer to it.

Q: What bodily defense can be acquired in an active or passive way, and can be natural or artificial?

A: immunity
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Q: What is a sac-like organ that stores urine?

A: the urinary bladder
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Q: Rainwater absorbs carbon dioxide (co 2 ) as it falls. the co 2 combines with water to form what?

A:
carbonic acid
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