Jay Leno is interview on the red carpet as he arrives at the Kennedy Center for the Performing Arts for the Mark Twain Prize for American Humor on Sunday, Oct. 19, 2014. (AP Photo/Kevin Wolf)
The human chin is something of a mystery to scientists. How, exactly, did we end up with a seemingly useless structure at the bottom of our face? One theory, as Smithsonian reported in 2012, is that they offer some support as we chew.