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 consistency, answers should be in all lower cased letters.

Category: SEX CHANGES
Clue: Don't let the pearls fool you, these lady bivalves can change into males when it suits them
oysters

Category: WORLD FLAGS
Clue: In 1996, to represent unity, Ethiopia put this 5-pointed star with mystical overtones on its flag
a pentacle

Category: UNITS OF MEASURE
Clue: Both the ounce & this unit of measure get their names from the Latin uncia, "twelfth part"
the inch