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: 7-LETTER WORDS 
Clue: It's from the Greek for "a place for watching"

SOLUTION: theater

PROBLEM: Category: ORGANIZATIONS 
Clue: It moved its HQ from Savannah to Wash. D.C. in 1913, & in 1917 began making each First Lady honorary pres.

SOLUTION: the girl scouts of the u.s.a.

PROBLEM: Category: THE WESTERN U.S. 
Clue: 2 popular places for swimming in this national park are in Firehole Canyon & at Boiling River

SOLUTION:
yellowstone