For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Yawns are more contagious among people with closer relationships.
163
Your thumb is about the same size as your nose.
124
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human brain doesn't stop developing until about 25 years old.
102