The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
The average person's skin weighs twice as much as their brain.
131
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Your heart will pump about 212 million liters in its lifetime.
26