But no matter how many times you've doodled one on a piece of paper or touched your chest when expressing affection for someone, there's probably a lot you don't know about it. So what are five things you don't know about your heart?
WHAT'S INSIDE: HUMAN BODY
- Body Parts
- Body Systems
You may never have thought about it (unless your child asks), but boogers are sticky for a perfectly logical scientific reason.
A vampire is headed straight for you. "I vant to drink your blood," he hisses. To prevent him from sucking the life force straight out of you, you decide to distract him with your amazing knowledge of blood. Take the quiz and prove yourself.