Enamel is hardest substance in the human body.
61
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The average sperm cell swims at 8 inches per hour.
76
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
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
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99