题干

下列有关生物学实验的研究方法或相应的分析中,正确的是(   )

A:在探究培养液中酵母菌数量的动态变化时,利用血球计数板进行酵母菌数量计数,实际上是利用了“标志重捕法”的原理

B:调查某一淡水区域的水质,若其pH过低,则可能是由于水中有机污染严重,导致厌氧微生物大量繁殖引起的

C:稀释红墨水对煮熟的和新鲜的玉米粒胚内部的染色情况不同,主要是由于温度对植物细胞膜上的载体活性的影响导致的

D:将质壁分离复原后的植物细胞用龙胆紫溶液染色,可用来观察细胞染色体的形态变化

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答案(点此获取答案解析)

B

同类题4

      London has a new magazine. But it is not printed(印刷) on paper. Everyone who has a television can receive it because it is on TV.
In order to read this magazine you have to have a decoder (解码器). Each page of it is numbered, so you only have to dial the number to choose which subject you want to read about. There are all kinds of information ---everything is included from cooking to the latest sports news.
       If you want to read the news, the first thing you have to do is to turn to the back page, which has an easy-to-remember page number, 100 for example. Then you start choosing what you want to read. The news is on page 101 to 109, so you put in the numbers and the news appears written across your screen. Perhaps you want to go out in the afternoon, so you press 181, and a brightly colored weather map appears on the screen. But the weather is terrible, so you decide to go shopping and dial 162 for a list of the week’s best bargains. But should you drive or take the train? To answer that question you only have to press 189 for the traffic report. It is very simple to use. But probably the best thing about the service is that it is being updated all the time. Journalists type new material directly onto the screen and the whole pages of the magazine can be replaced in minutes.
         London already has three services. One, sent out by TV, is called ORACLE while the other two, on BBC, are called CEEFAX because they let you see facts. Although CEEFAX and ORACLE have been operating for some time, they have not been well publicized(宣传). BBC engineers do not think that their idea will ever replace books and newspapers because they can be taken with you everywhere. But many people would agree that is a breakthrough(突破) as great as the invention of printing, which could not just change our reading habits but our whole way of life.