共享题干题 (二) High Blood Pressure阅读材料，回答下列的问题。 There is evidence that the usual variety of high blood pressure is，in part，a familial disease．Since families have similar genes as well as similar environment，familial diseases could be due to shared genetic influences，to shared environmental factors，or to both．For some years，the role of one environmental factor monly shared by families，namely dietary salt，has been studied at Brook—haven National Laboratory．These studies suggest that chronic excess salt ingestion(摄取)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 develop hypertension(高血压)whereas a few rapidly developed very severe hypertensions followed by early death．These marked variations were interpreted to result from differences in genetic constitution．By mating in successive generations only those animals that failed to develop hypertension from salt ingestion，a resistant strain(the R 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，a sensitive strain(the S strain)has also been developed． The availability of these two strains permits investigations not therefore possible．They provide a plausible laboratory model on which to investigate some clinical aspects of the human developing methods by which genetic susceptibility(敏感性)of human beings to high blood pressure can be defined without waiting for its appearance．1.[不定向选择题]The main idea of this passage is____________．A.Genetic constitution，or hereditary factor is all important factor that may underlie hypertension B.Excessive use of salt may cause high blood pressure C.Shared environmental factors may lead to familial disease D.There are two different kinds of strains in animals which cause their different reactions to excess salt ingestion 2.[不定向选择题]What can you infer from the passage?A.The experiments show that salt ingestion does not necessarily cause animals to develop hypertension bypretension with the environmental factors being equal. B.Dietary salt is harmful to human being's health. C.Human beings' high blood pressure will never be easily put under control. D.In order not to develop hypertension, man should consume chemically pure salt.
网友回答
1.参考答案：A
参考解析：根据第一段前两句话“There is evidence that the usual varieW of high blood pressure is，in part，a familial disease．Since families have similar genes as well as similar environment，familial diseases could be due to shared genetic influences，to shared environmental factors，or to both．”可知，有证据证明，在某种程度上，高血压是一种家族性疾病，因为家人有相似的基因，生活在相似的环境中，所以家族性疾病可归因于有共同的基因影响，共同的环境因素，或者两者都有，文章接着从遗传方面分析盐的摄入量与高血压的关系，所以选A。
2.参考答案：A
参考解析：B明显不符合原文；D文中没有提及；根据最后一段第二、三句话，C也错。3.[不定向选择题]The main difference between the "R" strain and the "S" strain lies in their____________．．A.quantities of salt consumed B.choice of mating partner C.blood pressure D.reaction to salt