题干

人的X染色体和Y染色体大小、形态不完全相同,但存在着同源区(Ⅱ)和非同源区(Ⅰ、Ⅲ),如图所示。下列有关叙述错误的是

A:Ⅰ片段上隐性基因控制的遗传病,男性患病率高于女性

B:Ⅱ片段上基因控制的遗传病,男性患病率可能不等于女性

C:Ⅲ片段上基因控制的遗传病,患病者全为男性

D:由于X、Y染色体互为非同源染色体,故人类基因组计划要分别测定

上一题 下一题 0.0难度 选择题 更新时间:2018-07-21 11:09:23

答案(点此获取答案解析)

D

同类题5

阅读理解

    One of the main challenges facing many countries is how to maintain their identity in the face of globalization and the growing multi-language trend. "One of the main reasons for economic failure in many African countries is the fact that, with a few important exceptions, mother-tongue education is not practiced in any of the independent African states." said Neville Alexander, Director of the Project for the Study of Alternative Education in South Africa at the University of Cape Town.

    In response to the spread of English and the increased multi-language trends arising from immigration, many countries have introduced language laws in the last decade. In some, the use of languages other than the national language is banned in public spaces such as advertising posters. One of the first such legal provisions(规定) was the 1994 "Toubon law" in France, and the idea has been copied in many countries since then. Such efforts to govern language use are often considered as futile by language experts, who are well aware of the difficulty in controlling fashions in speech and know from research that language switching among bilinguals is a natural process.

    It is especially difficult for native speakers of English to understand the desire to maintain the "purity" of a language by law. Since the time of Shakespeare, English has continually absorbed foreign words into its own language. English is one of the most mixed and rapidly changing languages in the world, but that has not been a barrier to acquiring superiority and power. Another reason for the failure of many native English speakers to understand the role of the state regulation is that it has never been the Anglo-Saxon way of doing things. English has never had a state-controlled authority for the language, similar, for example, to the Academic Francaise in France.

    The need to protect national languages is, for most western Europeans, a recent phenomenon—especially the need to ensure that English does not unnecessarily take over too many fields. Public communication, education and new ways of communication promoted by technology, may be key fields to defend.