Yawns are more contagious among people with closer relationships.
163
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Chewing gum boosts your brain power.
285
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Your body is creating and killing about 2.4 million red blood cells per second.
17