Your thumb is about the same size as your nose.
124
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The average sperm cell swims at 8 inches per hour.
76
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
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266