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]
What conclusion can be drawn from the karyo gkabt 2y0orpw 2c zj ze. *l1:8m1.kszgram bel z;pf g+b-mm35fsjx n-)m pt1qow?
A. Crossing over occurred during mitosis
B. Crossing over occurred during meiosis
C. Non-disjunction occurred during mitosis
D. Non-disjunction occurred during meiosis
参考答案: D
本题详细解析:
In the karyogram there are 3 copies of chromosome 21, this is known as trisomy and is the result of non-disjunction, which is when homologous chromosomes fail to separate during meiosis (Choice D). Choices A and B are incorrect as crossing over is not associated with trisomy. Choice C is incorrect as non-disjunction occurs during meiosis, not mitosis.
| 
