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问题 单项选择题

细胞内没有同源染色体的是( )

A．体细胞
B．精原细胞
C．初级精母细胞
D．次级精母细胞

答案

参考答案：D

解析： 同源染色体在减数分裂I后期彼此分离，因此次级精母细胞中不含同源染色体。

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       爱雨的人是不想躲开的。让那清凉的雨丝，洗去你心灵上的尘；让那安闲的雨丝，抹去你思维上的俗；让那多情的雨丝，________________；让那无声的雨丝，_______________。

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单项选择题

When you think of the Internet, you probably think of ".com." Just what do those three letters at the end of a World Wide Web address mean Every computer that hosts data on the Internet has a (71) numerical address. For example, the numerical address for the White House is 198.137.240.100. But since (72) people want to remember long strings of numbers, the (73) was developed. It is a critical part of the Internet’s technical infrastructure, correlates a numerical address to a word. To (74) the White House website, you could type its numerical address into the address box of your web browser. But most people prefer to use "www. whitehouse. gov." In this case, the domain name is (75) .

（75）处填（）。

A．www.

B．www. whitehouse

C．www. whitehouse. gov

D．whitehouse. gov
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