问题 填空题 案例分析题

玉米是一种雌雄同株的植物,其顶部开雄花,下部开雌花。在一个育种实验中,采用A、B两棵植株进行如图所示的杂交实验:

 

实验一:在杂交Ⅰ中,将植株A的花粉粒转移到同一植株的雌花上,授粉后,雌花发育成穗轴上的玉米粒。

实验二:在杂交Ⅱ中,植株B的花粉粒被转移到同一植株的雌花上,进行授粉。

实验三:在杂交Ⅲ中,植株A的花粉粒被转移到植株B的另一雌花上进行授粉。

上述三种杂交所获得玉米粒的颜色如下表所示:

用G代表显性性状,g代表隐性性状,则植株A的遗传因子组成为(),植株B的遗传因子组成为()。杂交Ⅰ的子代中,紫红色玉米粒的遗传因子组成是()。

答案

参考答案:g;gg;GG、Gg

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单项选择题

Comparisons were drawn between the development of television in the 20th century and the diffusion of printing in the 15th and 16th centuries. Yet much had happened between. As was discussed before, it was not until the 19th century that the newspaper became the dominant pre- electronic (61) , following in the wake of the pamphlet and the book and in the (62) of the periodical. It was during the same time that the communications revolution (63) UP, beginning with transport, the railway, and leading on through the telegraph, the telephone, radio, and motion pictures into the 20th-century world of the motor car and the air plane. Not everyone sees that process in (64) . It is important to do so.

It is generally recognized, (65) , that the introduction of the computer in the early 20th century, (66) by the invention of the integrated circuit during the 1960s, radically changed the process, although its impact on the media was not immediately (67) . As time went by, computers became smaller and more powerful, and they became "personal" too, as well as (68) , with display becoming sharper and storage (69) increasing. They were thought of, like people, (70) generations, with the distance between generations much (71) .

It was within the computer age that the term "information society" began to be widely used to describe the (72) within which we now live. The communications revolution has (73) both work and leisure and how we think and feel both about place and time, but there have been (74) view about its economic, political, social and cultural implications. "Benefits" have been weighed (75) "harmful" outcomes. And generalizations have proved difficult.

(70)处填()。

A.by means of

B.in terms of

C.with regard to

D.in line with