Do I Know You? An animatronic baby Tyrannosaurus Rex gives students a close look during a preview of the Australian show Walking With Dinosaurs in Melbourne last week. Mark Dadswell/Getty Images hide caption

itoggle caption Mark Dadswell/Getty Images

Stone artifacts dating back 15,500 years suggest humans may have arrived 2,000 years earlier than previously thought. Courtesy of Michael R. Waters hide caption

itoggle caption Courtesy of Michael R. Waters

According to Dr. Lidy Pelsser's study, 64 percent of children diagnosed with ADHD are actually experiencing a hypersensitivity to food. iStockphoto.com hide caption

itoggle caption iStockphoto.com

The FBI used a new DNA fingerprinting technology to analyze the anthrax used in the 2001 mailings. These anthrax spores can live for many years. Janice Haney Carr/CDC Public Health Image Library hide caption

itoggle caption Janice Haney Carr/CDC Public Health Image Library