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: BODY LANGUAGE 
Clue: It's what you're said to "hold" when you're keeping your big mouth shut
your tongue

Category: THE "SKY" IS FALLING 
Clue: America's first space station
skylab

Category: PRESIDENTS & FIRST LADIES 
Clue: Before reaching the Oval Office, this bachelor president served as minister to Russia in the 1830s

james buchanan