Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your body is creating and killing about 2.4 million red blood cells per second.
17
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Your thumb is about the same size as your nose.
124
Yawns are more contagious among people with closer relationships.
163
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266