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Did you know?
Vaccines prevent between 2.5 and 4 million deaths every year.
Did you know?
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Did you know?
Your heart beats over 36 million times a year.
Did you know?
There are 20 feet of blood vessels in each square inch of human skin.
Did you know?
Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.

