1. Human thigh bones are stronger than concrete.
2. The average human body contains enough: iron to make a 3 inch nail, sulphur to kill all fleas on an average dog, carbon to make 900 pencils, potassium to fire a toy cannon, fat to make 7 bars of soap, phosphorous to make 2,200 match heads, and water to fill a ten-gallon tank.
3. More people are allergic to cow’s milk than any other food.
5. Your heart beats over 100,000 times a day! Your ribs move about 5 million times a year, every time you breathe!
6. You are born with 300 bones, but by the time you become an adult, you only have 206.
8. One quarter of the bones in your body, are in your feet!
9. It is impossible to sneeze with your eyes open.
10. Right handed people live, on average, nine years longer than left-handed people.
11. Beards are the fastest growing hairs on the human body. If the average man never trimmed his beard, it would grow to nearly 30 feet long in his lifetime.
12. Like fingerprints, everyone’s tongue print is different!
13. Fingernails grow nearly 4 times faster than toenails!
14. Most dust particles in your house are made from dead skin!
15. The present population of 6 billion plus people of the world is predicted to become 15 billion by 2080. The only time the human population declined was in the years following 1347, the start of the epidemic of the plague ‘Black Death’ in Europe.
16. Women blink nearly twice as much as men.
17. The human brain is 78% water.
18. An average person uses the bathroom 6 times per day.
19. An individual blood cell takes about 60 seconds to make a complete circuit of the body.
20. Laughing lowers levels of stress hormones and strengthens the immune system. Six-year-olds laugh an average of 300 times a day. Adults only laugh 15 to 100 times a day.
I can't verify these. I came across them somewhere on the net looking for fact 2.