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.

[Q]: Category: SIGNS & SYMBOLS 
Clue: Created in 1970 & made up of 3 arrows, the universal symbol for this was based on the Mobius strip
[A]: recycling


[Q]: Category: U.S. POPULATION 
Clue: Between 2000 & 2010 these 2 states that border each other led the nation in highest percentage of population increase, 35% & 25%
[A]: arizona and nevada


[Q]: Category: BESTSELLING AUTHORS 
Clue: He had the year's bestselling novel a record 7 years in a row with 7 different titles, ending in 2000
[A]:
john grisham