Passage1Lonelypeople,itseems,a-考网

Passage 1

Lonely people, it seems, are at greater risk than the gregarious of developing illnessesassociated with chronic inflammation, such as heart disease and certain cancers. A paper publishedlast year in the Public Library of Science, Medicine, shows the effect on mortality of loneliness iscomparable with that of smoking and drinking after examining the results of 148 previous studiesand controlled for factors such as age and pre-existing illness.

Steven Cole of the University of California, Los Angeles, thinks he may know why this is so.

He told the American Association for the Advancement of Science meeting in Washington, D.C.,about his work studying the expression of genes in lonely people. Dr. Cole harvested samples ofwhite blood cells from both lonely and gregarious people. He then analysed the activity of theirgenes, as measured by the production of a substance called messenger RNA. This molecule carriesinstructions from the genes telling a cell which proteins to make. The level of messenger RNA frommost genes was the same in both types of people. There were several dozen genes, however, thatwere less active in the lonely, and several dozen others that were more active. Moreover, both theless active and the more active gene types came from a small number of functional groups.

Broadly speaking, the genes less active in the lonely were those involved in staving off viralinfections. Those that were more active were involved in protecting against bacteria. Dr. Colesuspects this could help explain not only why the lonely are iller, but how, in evolutionary terms, thisodd state of affairs has come about.

The crucial bit of the puzzle is that viruses have to be caught from another infected individualand they are usually species-specific. Bacteria, in contrast, often just lurk in the environment, andmay thrive on many hosts. The gregarious are therefore at greater risk than the lonely of catchingviruses, and Dr. Cole thus suggests

A.helped to avoid infections resulting from viruses
B.participated in guarding against bacteria
C.came from a few different functional groups
D.existed only as a small group

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答案： B

本题解析：

细节题。根据题干信息定位到第三段的前两句。这两句讲述孤独的人体内活性较低的基因是那些帮助人们避开病毒感染的基因。而那些活性较高的基因帮助人们抵抗细菌，因此答案为B项。文中提到避开病毒感染的基因是孤独的人体内活性较低的基因．故排除A项。第二段末句说无论是活性较高的基因还是活性较低的基因都来自少数功能群，与C项矛盾。D项在原文未提及．故排除。