1. If you flick your nipple, it will become hard in seven seconds. Catchlights_sg / Getty Images Try it. 2. Your body contains enough chlorine to disinfect five swimming pools. Slonme / Getty Images It also contains enough carbon to make 9,000 pencils. 3. Your heartbeat will sync to the rhythm of the music that you're listening to. Avector / Getty Images, Maxshot / Getty Images A study showed that crescendos led to a temporary increase in blood pressure and heart rate, which went back down during the decrescendo. 4. And you produce enough saliva in your lifetime to fill two swimming pools. Kuramyndra / Getty Images The consistency of said swimming pools would be different from person to person. 5. Combined, a full head of hair is strong enough to support the weight of two elephants without breaking. Chokja / Getty Images That's 12 tons. 6. Your sneeze travels as fast as a race car. Peopleimages / Getty Images, Ehstock / Getty Images It launches out of you at 100 miles per hour. 7. Bacteria in your body outnumber people on the earth 4:1. Bet_noire / Getty Images We have over 30 trillion bacteria on our body at any given time. 8. Your teeth are as strong as shark teeth. Violetastock / Getty Images The only reason we have to use knives and sharks don't is because of the shape of our teeth, not their durability. 9. Dirty hair can improve air quality. Softulka / Getty Images The oil from your scalp can absorb air pollutants. 10. You have way more than five senses. Sudowoodo / Getty Images In addition to sight, smell, sound, touch, and taste, you also have proprioception, thermoception, nociception, temporal perception, and equilibrioception, which are the sense of space, sense of temperature, sense of pain, sense of time, and sense of balance respectively. 11. You make more earwax when you're stressed or anxious. Vladimirfloyd / Getty Images And sometimes wearing earbud headphones clogs it up. 12. It's impossible to tickle yourself. Jeremkin / Getty Images Your body predicts it. 13. You share over 50% of your genes with bananas. Chubarovy / Getty Images You also share over 50% of your genes with chickens. 14. 300 million cells die on your body every minute. Benjamin Toth / Getty Images Its OK, because you have 50–100 trillion cells to work with. 15. The entire surface of your skin is replaced nearly once a month. Delmaine Donson / Getty Images That means you shed 30,000 to 40,000 skin cells per day. 16. Enough adrenaline can give you super strength, like the ability to lift a car. Dragana991 / Getty Images Aside from helping your muscles, it also heightens recollection and increases respiration. 17. You're bioluminescent. Duncanl / Getty Images That's right, you glow. The light just isn't perceptible to the human eye.