Yawns are more contagious among people with closer relationships.
163
The human brain doesn't stop developing until about 25 years old.
102
Your thumb is about the same size as your nose.
124
Every year your body replaces 98% of your atoms.
119
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
It takes about 20 seconds for a red blood cell to circle the whole body.
102
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
The average sperm cell swims at 8 inches per hour.
76