"All it would take is one sneeze. Your DNA would be all over this book. That's right. Your spit has DNA in it. So does your skin. And your blood. That's important to police because everyone's DNA is different. With the right equipment, detectives can match a person with some blood left at a crime scene. They've put murderers in jail that way. They've also freed innocent people. Want to know more? Get some evidence about the following: how almost everything...