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问题 选择题

有些植物的茎能不断加粗，有些植物的茎却不能长的很粗，与此相关的结构是： 

A．木质部

B．韧皮部

C．形成层

D．导管和筛管

答案

答案：C

题目分析：在树皮以内有一层分生组织，叫形成层，形成层的细胞不断的侧向分裂增生，其中，大部分细胞向内形成木质部，少量细胞向外形成韧皮部，从而使得树干不断地生长加粗，故选B。

单项选择题

Samuel Goldstein, CFA, is an analyst for Tamarack Securities. Goldstein’s father, Reuben, has a client account at Tamarack. In ordering trades, Goldstein should place orders in:（）

A. his clients’ accounts first, his father’s account second, and his account last.

B. his clients’ and his father’s accounts in the first group and his personal accounts in the second group.

C. his clients’ accounts in the first group and his father’s and his own personal account in the second group.
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判断题

构成投资组合的证券A和证券B，其标准离差分别为14%和8%。在等比例投资的情况下，如果二种证券的相关系数为1，该组合的标准离差为11%；如果两种证券的相关系数为-1，则该组合的标准离差为3%。( )
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