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
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Enamel is hardest substance in the human body.
61
The human brain doesn't stop developing until about 25 years old.
102
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
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18