In 1656 Christiaan Huygens improved clocks by adding what to them?

Chris Sanders, Barry Sanders and Deion Sanders all played which sport professionally? Chris Stevens, Maggie O'Connell and Dr. Joel Fleischman were characters on which TV series? The orbiter Columbia, whose name honors the spirit of Christopher Columbus, was the first vehicle of which NASA program… Chris Columbus wrote which 1984 film directed by Joe Dante, but not its 1990 sequel? Which Christian Dior fragrance with a deadly name was introduced in 1985? In 1659 Christiaan Huygens published a correct explanation of which planet's rings? Christian Nelson of Onawa, Iowa, created which chocolate-coated ice cream bar in 1921? Christian, Rory, Kieran, Quinn, Shane, Dakota and Macaulay are siblings from which acting family?