The human brain doesn't stop developing until about 25 years old.
102
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
Your thumb is about the same size as your nose.
124
The average sperm cell swims at 8 inches per hour.
76
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Yawns are more contagious among people with closer relationships.
163
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127