What's the Kennection? #21

Welcome to Kennections, a weekly quiz created by Jeopardy! champion/co-host Ken Jennings. Here's how to play: All five answers to the questions below have something in common. Can you figure it out? (Note: We've given you a hint by showing you how many letters are contained within the answer, but this quiz is not interactive.)

1.  Beginning at the Battle of Loos, World War I veterans reported a stress disorder, or “shock,” named for the explosion of what?

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2.  What Procter & Gamble brand is the world’s best-selling laundry detergent? 

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3.  In the British version of Monopoly, posh Mayfair is the equivalent of which American property?

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4.  What 1980s band was led by Mike Score, who got his iconic hairstyle when the bassist flattened his attempt at a “Ziggy Stardust” look?

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5.  In a 2002 Star Wars movie, Anakin infamously reveals that he doesn’t like what, because it’s “rough and irritating”?

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