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: NEWSPAPERS 
Clue: In 1868 the 1st edition of this annual reference book was published by the New York World
the world almanac

Category: U.S. RIVERS 
Clue: The Falls of Saint Anthony stop this mighty river from being navigable north of St. Paul, Minnesota
the mississippi

Category: LAWN ORDER 
Clue: Perhaps to save the cost of cutting the White House lawn during World War I, these animals were grazed there

sheep