GUT CHECK: The curious can find out just what’s living in their intestines. “The bacterial zoo inside your gut could look very different if you’re a vegetarian or an Atkins low-carb dieter, a couch potato or an athlete, fat or thin. Now for a fee — $69 and up — and a stool sample, the curious can find out just what’s living in their intestines and take part in one of the hottest new fields in science.”