Yawns are more contagious among people with closer relationships.
163
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Your body is creating and killing about 2.4 million red blood cells per second.
17
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The average sperm cell swims at 8 inches per hour.
76
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13