Yawns are more contagious among people with closer relationships.
163
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The human body contains over a billion miles of DNA.
147
Our Right Lungs takes more air than our left lung.
194