Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The average person's skin weighs twice as much as their brain.
131
Enamel is hardest substance in the human body.
61
It takes about 20 seconds for a red blood cell to circle the whole body.
102
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118