2. 外语
  3. Helicobacter pylori is one of humanity’s oldest and closest companions, and yet it took scientists more than a century to recogn

Helicobacter pylori is one of humanity’s oldest and closest companions, and yet it took scientists more than a century to recogn

admin2013-01-12  43
问题     Helicobacter pylori is one of humanity’s oldest and closest companions, and yet it took scientists more than a century to recognize it. As early as 1875, German anatomists found spiral bacteria colonizing the mucus layer of the human stomach, but because the organisms could not be grown in a pure culture, the results were ignored and then forgotten. It was not until 1982 that Australian doctors Barry J. Marshall and J. Robin Warren isolated the bacteria, allowing investigations of H. pylori’s role in the stomach to begin in earnest. Over the next decade, researchers discovered that people carrying the organisms had an increasing risk of developing peptic ulcers-breaks in the lining of the stomach or duodenum and that H. pylori could also trigger the onset of the most common form of stomach cancer.
    Just as scientists were learning the importance of H. pylori, however, they discovered that the bacteria are losing their foothold in the human digestive tract. Whereas nearly all adults in the developing countries would still carry the organism, its prevalence is much lower in developed countries such as the U S. Epidemiologists believe that H. pylori has been disappearing from developed nations for the past 100 years thanks to improved hygiene, which blocks the transmission of the bacteria, and to the widespread use of antibiotics. As H. pylori has retreated, the rates of peptic ulcers and stomach cancer have dropped. But at the same time, diseases of the esophagus—including acid reflux disease and a particularly deadly type of esophageal cancer—have increased dramatically, and a wide body of evidence indicates that the rise of these illnesses is also related to the disappearance of H. pylori.
The author’s primary purpose in writing this passage is to______.
选项 A、warn people of the harm of H. pylori colonization of the stomach
B、make people aware of the harm of eradicating H. pylori from the stomach
C、suggest that the benefits of eradicating H. pylori from the stomach are not outweighed by the potential harm
D、call attention to the consequences of eradicating H. pylori from the stomach
答案C
解析 文中第一段阐述了科学家对幽门螺旋菌的认识过程，最后一句话指出了幽门螺旋菌的危害；第二段中描述了幽门螺旋菌渐渐消逝，而这又可能诱发了其他的一些食道疾病。因而，从整篇文章来看，作者意在暗示根除幽门螺旋菌并不比潜在的危害更有益，故正确答案为C。
转载请注明原文地址:https://kaotiyun.com/show/hp9O777K
0

考博英语

相关试题推荐
随机试题
最新回复(0)