Flu shots only work about 70% of the time.
18
Your skeleton keeps growing until you are about 35, then you start to shrink.
74
Like fingerprints, everyone's tongue print is different!
71
You mostly breathe from only one nostril at a time!
75
Fingernails grow nearly 4 times faster than toenails.
31
During a typical human life span, the human heart will beat approximately 2.5 billion times.
21
Men have larger hearts; women's hearts beat faster.
77
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22