Yawns are more contagious among people with closer relationships.
163
The average person's skin weighs twice as much as their brain.
131
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The human brain doesn't stop developing until about 25 years old.
102
The largest cell in the human body is the female egg and the smallest is the male sperm.
682