Enamel is hardest substance in the human body.
61
Yawns are more contagious among people with closer relationships.
163
Our Right Lungs takes more air than our left lung.
194
The human body contains over a billion miles of DNA.
147
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46