You probably have a vague idea that cavities come from eating sugar and not brushing, but what exactly is going on in there? This video introduces us to the bacteria in our mouth that cause cavities -- and the friendly ones that round out the ecosystem.

If you skipped the gym this morning, make it up now with this ten-minute workout. It's focused on your core and requires no equipment, just bodyweight moves -- but it's intense enough to get your heart pumping and give you a mini cardio workout.