Your fingernails grow faster in summer.
744
The average person's skin weighs twice as much as their brain.
131
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
A person will create enough saliva to fill two average size swimming pools during his lifetime.
191
Tigers can see 6 times better at night than humans.
305
Having sex can make a woman look younger and more attractive due to the release of estrogen and collagen.
346
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11