The average sperm cell swims at 8 inches per hour.
76
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Your thumb is about the same size as your nose.
124
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The average person's skin weighs twice as much as their brain.
131
It takes about 20 seconds for a red blood cell to circle the whole body.
102