Yawns are more contagious among people with closer relationships.
163
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Every year your body replaces 98% of your atoms.
119
The human brain doesn't stop developing until about 25 years old.
102
The human brain uses approximately as much energy as a 10 watt light bulb.
120
When you take a step, you are using up to 200 muscles.
886
The average person's skin weighs twice as much as their brain.
131