搜题请搜索小程序“爱下问搜题”
问题 选择题

下列关于基因的描述，错误的是

A．基因位于DNA上

B．性状相同，基因组成不一定相同

C．基因含有特定的遗传信息

D．基因都是成对存在的

答案

答案：D

基因在体细胞中是成对存在的，但在生殖细胞中就不是成对存在的。

单项选择题

下列关于禽流感病毒的说法，哪一项正确（）

A.禽流感病毒属于冠状病毒群

B.因其只能感染家禽而得名

C.基因组为分节段单股负链RNA

D.已有15个H亚型和9个N亚型

E.病毒形状均为球形
查看答案
单项选择题

Who won the World Cup 1994 football game What happened at the United Nations How did the critics like the new play (1) an event takes place, newspapers are on the streets (2) the details. Wherever anything happens in the world, reporters are on the spot to (3) the news.
Newspapers have one basic (4) , to get the news as quickly as possible from its source, from those who make it to those who want to (5) it.
Radio, telegraph, television, and (6) inventions brought competition for newspaper. So did the development of magazines and other means of communication. (7) , this competition merely spurred the newspapers on. They quickly made use of the newer and faster means of communication to improve the (8) and thus the efficiency of their own operations. Today more newspapers are (9) and read than ever before. Competition also led newspapers to branch out into many other fields. Besides keeping readers (10) of the latest news, today’s newspapers (11) and influence readers about politics and other important and serious matters. Newspapers influence readers’ economic choices (12) advertising. Most newspapers depend on advertising for very (13) .
Newspapers are sold at a price that (14) even a small fraction of the cost of production. The main (15) of income for most newspapers is commercial advertising. The (16) in selling advertising depends on a newspaper’s value to advertisers. This (17) in terms of circulation. How many people read the newspaper
Circulation depends (18) on the work of the circulation department and on the services or entertainment (19) in a newspaper’s pages. But for the most part, circulation depends on a newspaper’s value to readers as a source of information (20) the community, city, county, state, nation, and world—and even outer space.

[A] reason [B] cause [C] problem [D] purpose
查看答案