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Author Question: A ________ is a central, open area inside a tubular structure, such as the esophagus, small ... (Read 54 times) |
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
Although the Roman numeral for the number 4 has always been taught to have been "IV," according to historians, the ancient Romans probably used "IIII" most of the time. This is partially backed up by the fact that early grandfather clocks displayed IIII for the number 4 instead of IV. Early clockmakers apparently thought that the IIII balanced out the VIII (used for the number 8) on the clock face and that it just looked better.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
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.
Your chance of developing a kidney stone is 1 in 10. In recent years, approximately 3.7 million people in the United States were diagnosed with a kidney disease.