Yawns are more contagious among people with closer relationships.
163
Every year your body replaces 98% of your atoms.
119
The human brain doesn't stop developing until about 25 years old.
102
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Enamel is hardest substance in the human body.
61
One human hair can support 3 ounces.
191
When you take a step, you are using up to 200 muscles.
886
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22