It takes about 20 seconds for a red blood cell to circle the whole body.
102
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Poor eyesight (myopia) is associated with higher IQ.
232
Yawns are more contagious among people with closer relationships.
163
Your body is creating and killing about 2.4 million red blood cells per second.
17
Your thumb is about the same size as your nose.
124