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Author Question: The above figure shows the labor market for land surveyors. Dave is a land surveyor. What is the tax ... (Read 55 times) |
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.
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.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Prostaglandins were first isolated from human semen in Sweden in the 1930s. They were so named because the researcher thought that they came from the prostate gland. In fact, prostaglandins exist and are synthesized in almost every cell of the body.
In 2010, opiate painkllers, such as morphine, OxyContin®, and Vicodin®, were tied to almost 60% of drug overdose deaths.