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.

Category: LAW 
Clue: In Latin legal lingo it means "by the fact itself"
ipso facto

Category: POWER TO THE PEOPLE 
Clue: Citizen's Eco-Drive Thermo is one of these powered by the heat of your body
wristwatch

Category: LITERATURE 
Clue: The only thing this "Wizard of Oz" character was afraid of was "a lighted match"

the scarecrow