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.

Example Input: Category: THE ROTARY CLUB 
Clue: On an airplane they're "fixed"; on a helicopter they're actually "rotary"
Example Output: wings

Example Input: Category: RIVERS 
Clue: The mouth of this 2315-mile-long river lies in the Mississippi River 17 miles above St. Louis
Example Output: the missouri

Example Input: Category: BIOLOGY 
Clue: Around 1940 scientists found that mutations in these chromosomal units result in defective enzymes
Example Output:
genes