Your body is creating and killing about 2.4 million red blood cells per second.
17
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
Your thumb is about the same size as your nose.
124
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Enamel is hardest substance in the human body.
61
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18