下列关于生物膜和物质运输的有关叙述中，不正确的是（） A.细胞

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问题单项选择题

下列关于生物膜和物质运输的有关叙述中，不正确的是（）

A.细胞膜和液泡膜等生物膜都是选择透过性膜

B.植物细胞的原生质层相当于一层半透膜

C.小分子物质都能通过细胞膜，大分子物质则不能

D.细胞的吸水和失水是水分子顺相对含量的梯度跨膜运输的结果

答案

参考答案：C

单项选择题

48 （单项选择题）

A.Thompson was shocked and devastated.

B.Another trial was held.

C.I cannot begin to imagine what would have happened had my mistaken identification occurred in a capital case.

D.During the attack, she made an effort to memorize every detail of his face , looking for scars , tattoos (纹身) or other identifying marks.Jennifer

E.Many criminals are sent to prison on the basis of accurate testimony by eyewitnesses.

F.Jennifer Thompson decided to meet Cotton and apologize to him personally.

单项选择题

在SQL中，基本表的撤销(从数据库中删除表)可以用( )命令。

A．DROP SCHEMA

B．DROP TABLE

C．DROP VIEW

D．DROP INDEX