environment factor commonly shared by families, namely dietary salt , has been studied at Brookhaven National Laboratory. These studies suggest that long excess salt intake can lead to high blood pressure in man and animals. Some individuals, however, and some rats consume large amounts of salt without developing high blood pressure. No matter how strictly all environmental factors were controlled in these experiments, some salt-fed animals never developed hypertension whereas a few rapidly developed very severe hypertension followed by early death. These marked variations were interpreted to result from differences in genetic constitution.
By mating long successive generations of those animals that failed to develop hypertension from salt intake, a resistant strain has been evolved in which consumption of large quantities of salt fails to influence the blood pressure significantly. In contrast, by mating only animals that quickly develop hypertension from salt, sensitive strain has also been developed.
The availability of these two strains permits investigations possible. They provide a plausible laboratory model on which to investigate some clinical aspects of the human hypertension. More important, there might be the possibility of developing methods by which genetic susceptibility of human beings to high blood pressure can be defined without waiting for its appearance. Radioactive sodium 22 was an important tool in working out the characteristics of the sodium chloride metabolism.
21. The study of the effects of salt on high blood pressure was carried out_______.
A. as members of the same family tend to use similar amounts of salt
B. to explore the long-term use of a sodium based substance
C. because it was proven that salt caused high blood pressure
D. because of the availability of chemically pure salt and its derivatives
22. The main difference between S and R rats is their_______.
A. need for sodium 22 B. rate of mating
C. reaction to salt D. type of blood
23. We can infer from the article that sodium 22 can be used to_______.
A. control high blood pressure
B. cure high blood pressure caused by salt
C. tell the S rats from the R rats
D. determine what a sodium chloride metabolism is like
24. The most beneficial results of the research might be_______.
A. development of diets free of salt
B. an early cure for high blood pressure
C. control of genetic agents that cause high blood pressure
D. the early identification of potential high blood pressure victims
25. Which of the statements best relates the main idea of this article?
A. When salt is added rats and human beings react similarly.
B. The near future will see a cure for high blood pressure.
C. The medical field is desperately in need of research.
D. A tendency toward high blood pressure may be a hereditary factor.
21. A 22. C 23. D 24. D 25. D
上一篇: 六级冲刺练习:阅读(104)
下一篇: 六级冲刺练习:阅读(125)
习近平主席2018年新年贺词中的几个典故
国内英语资讯:Chinas financial sector offers better support for real economy
国际英语资讯:Spotlight: Pakistan, U.S. at crossroad following Trumps fresh accusations
国际英语资讯:Japanese mayor under fire for threatening to kill reporter
国内英语资讯:Birth centenary of late senior political advisor commemorated
国际英语资讯:Russia rejects U.S. proposal for UN emergency meeting on Iran
国际英语资讯:Roundup: S.Korea, U.S. agree not to conduct joint war games during 2018 Winter Olympics
美国的房产中介推出神奇新服务:帮你看看是否闹鬼
老做恶梦?科学家全面解析背后的含义
体坛英语资讯:Guangsha beat Shenzhen to keep position in CBA league
青海省西宁二十一中2017-2018学年高二上学期12月月考英语试卷
Trail, track and trace 和“追踪、踪迹”有关的三个词
体坛英语资讯:Chinas star weightlifter Shi dominates mens 73kg at world championships
国内英语资讯:Chinese vice premier urges full completion of clearing arrears task
2020东京奥运会:参赛人员将“刷脸”进场
国内英语资讯:China Focus: China to optimize business environment
支付宝给你的2018关键词准吗? 这些词用英语怎么说?
给你100万元 你愿意把你的脸卖给机器人吗?
Father’s Present 父亲的礼物
无聊的工作会议让你神游?永远不要为此感到愧疚