The average person's skin weighs twice as much as their brain.
131
Only humans shed emotional tears.
331
Early American humans hunted car-size armadillos and used their shells for houses.
12
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
By weight, Bone is five times stronger than steel.
417
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
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
Your thumb is about the same size as your nose.
124