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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.
Acute bronchitis is an inflammation of the breathing tubes (bronchi), which causes increased mucus production and other changes. It is usually caused by bacteria or viruses, can be serious in people who have pulmonary or cardiac diseases, and can lead to pneumonia.
There are actually 60 minerals, 16 vitamins, 12 essential amino acids, and three essential fatty acids that your body needs every day.
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.
Vaccines prevent between 2.5 and 4 million deaths every year.