Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
One human hair can support 3 ounces.
191
Enamel is hardest substance in the human body.
61
Chewing gum boosts your brain power.
285
If your DNA was stretched out it would reach to the moon 6,000 times.
256
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13