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Author Question: How many stages does the demographic transitionas in Europehave? a. One b. Two c. Three or four ... (Read 10 times) |
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
In 1864, the first barbiturate (barbituric acid) was synthesized.
In the United States, an estimated 50 million unnecessary antibiotics are prescribed for viral respiratory infections.
Throughout history, plants containing cardiac steroids have been used as heart drugs and as poisons (e.g., in arrows used in combat), emetics, and diuretics.