Enamel is hardest substance in the human body.
61
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Poor eyesight (myopia) is associated with higher IQ.
232
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217