It takes about 20 seconds for a red blood cell to circle the whole body.
102
Yawns are more contagious among people with closer relationships.
163
The average person's skin weighs twice as much as their brain.
131
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266