|
Author Question: If researchers find negative results, they should a. redesign the study to correct for any ... (Read 68 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.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Symptoms of kidney problems include a loss of appetite, back pain (which may be sudden and intense), chills, abdominal pain, fluid retention, nausea, the urge to urinate, vomiting, and fever.
It is difficult to obtain enough calcium without consuming milk or other dairy foods.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.