Sure, modern person, you can rattle off your bra size, your cell-phone minutes, and your credit rating in no seconds flat, but what do you really know about your carbon footprint? It's hard to quantify it with a number, but we've assembled a handy quiz to help you get a sense of just how green you are. Here, then, are 25 questions that'll separate the panda-killers from the eco-saints: we'll tell you which one you are after you've clicked through to the end.