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.

Q: Category: THE DIGESTIVE SYSTEM 
Clue: Gravity isn't required to move food down to your stomach; this process moves it down the esophagus

A: peristalsis
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Q: Category: NONFICTION 
Clue: This 1988 bestseller was subtitled "From the Big Bang to Black Holes"

A: a brief history of time
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Q: Category: WHISTLER 
Clue: Whistler moved to London in 1859 & painted this river often, including "In Ice" in 1860

A:
the thames
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