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Author Question: An example of a single-purpose piece of equipment is a a. set of parallel bars. b. sandbox. c. ... (Read 51 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.
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.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Dogs have been used in studies to detect various cancers in human subjects. They have been trained to sniff breath samples from humans that were collected by having them breathe into special tubes. These people included 55 lung cancer patients, 31 breast cancer patients, and 83 cancer-free patients. The dogs detected 54 of the 55 lung cancer patients as having cancer, detected 28 of the 31 breast cancer patients, and gave only three false-positive results (detecting cancer in people who didn't have it).
About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.