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Did you know?
Blood is approximately twice as thick as water because of the cells and other components found in it.
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?
Approximately 500,000 babies are born each year in the United States to teenage mothers.
Did you know?
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Did you know?
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.