Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human body contains over a billion miles of DNA.
147
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118