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问题 单项选择题

对精囊腺癌的描述错误的是（）

A.肿物位于前列腺后上方、膀胱底部

B.可见于年轻人，也可见于老人

C.肿物可阻塞输尿管下段和 * *

D.所有的精囊腺癌与前列腺癌的组织学形态容易区分

E.大多数患者由于不能彻底外科切除而预后不良

答案

参考答案：D

解析：精囊腺癌是来源于精囊被覆上皮的恶性肿瘤，有的被覆高柱状上皮伴微 * * ，形态似前列腺导管腺癌。因此本题应选D，其他选项均正确。

单项选择题

下列关于契约型证券投资基金性质的说法中，正确的是（）．

A.证券投资基金属于债权类合同或契约，基金管理人对持有人负有完全的法定偿债责任；

B.证券投资基金属于信托契约，基金管理人只是代替投资者管理资金，并不保证资金的收益率，投资人也要承担一定的风险和费用.

C.证券投资基金实行专家理财，基金管理人没有义务向基金持有人披露有关基金运作信息.

D.证券投资基金的收益主要来源于持有证券的股息、红利和利息收入
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单项选择题

About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids.

It can be inferred from the passage that, in the early spring, the buds of plants________.

A．export protein in the form of amino acids

B．do not require water

C．have begun photosynthesizing

D．obtain organic compounds from the root
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