Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Poor eyesight (myopia) is associated with higher IQ.
232
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human body contains over a billion miles of DNA.
147
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
The average sperm cell swims at 8 inches per hour.
76
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
The human brain doesn't stop developing until about 25 years old.
102