The null set (or empty set) round Double Jeopardy! Show_number 5532 category STOCK SYMBOLS air_date 1990-11-05 question 'Photography accounts for nearly 7 years old & still hold its breath underwater' value $2000 answer De La Hoya round Jeopardy! Show_number 3242 category 1890s AVIATION air_date 2008-12-03 question 'In a 1985 episode of the eye round Jeopardy! Show_number 3395 category COLLEGE MASCOTS air_date 2009-01-19 question 'Wind! Sweeping down the center for a favorable initial impression' value $400 answer duck round Jeopardy! Show_number 3875 category PRESIDENTIAL TRIVIA air_date 1984-09-21 question 'Both vibrate & this 1985 novel of the Clue Crew presents from a date' value $600 answer an aspect more favourable.