You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
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Question: Category: MR. BODY 
Clue: Fed by the hepatic portal veins, it weighs about a pound more in men than in women

Answer: liver


Question: Category: __E__E__E 
Clue: A form of address for some royalty, it means calm & unruffled

Answer: serene


Question: Category: BIOLOGY 
Clue: When sexually aroused, the carpenter species of this insect will chase jet liners

Answer:
bees