Continuity and Change D.4 Cell & Nuclear Division (id: a7fc04e4c)

本题目来源于试卷: Continuity and Change D.4 Cell & Nuclear Division，类别为 IB生物学

[单选题]
This karyogram is for an individupizh*0u ddz 5jkw;68mqd a3 ;qal witxe*xsz /- shu2b;.w1 ixsr br 66rec,gh Down syndrome.

Which statement is not correct?

A. Down syndrome is caused by trisomy 21
B. Down syndrome is caused by a trisomy of sex chromosomes
C. Down syndrome is caused by a trisomy of autosomes
D. Down syndrome is caused by an incorrect number of chromosomes


参考答案:  B


本题详细解析:
Down syndrome is not caused by a trisomy of sex chromosomes (choice B). The other statements are correct. Down syndrome is caused by trisomy 21 (choice A). It is caused by a trisomy of autosomes (choice C) because chromosome 21 is an autosome. Down syndrome is caused by an incorrect number of chromosomes (choice D).

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