TASK DEFINITION: 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.
PROBLEM: Category: "FIRST" CHRONICLES 
Clue: There is reddening of the epidermis but no blistering in this

SOLUTION: a first-degree burn

PROBLEM: Category: U.S. GEOGRAPHY 
Clue: In 1937 the government set aside this Georgia swamp as a national wildlife refuge

SOLUTION: okefenokee swamp

PROBLEM: Category: HISTORY 
Clue: The last Abbasid Caliph was killed in 1258 when these Asian warriors sacked Baghdad

SOLUTION:
the mongols