单选题利用以下信息解答问题(1)～(3)：两种纯系玉米穗轴的平均长度分别为0.27m和0.09m。在该性状中包含的多基因都表现出加性基因作用。

单选题谁是第一个在进化领域中提出了一个有条理的理论?( )

单选题香蕉是一个同源三倍体，3n=33。在减数分裂时就可能出现______等不同的联会方式，造成后期工不均衡分离，形成的配子基本上都是不育的。 A．三价体和四价体 B．三价体、二价体和单价体 C．二价体和单价体 D．三价体和单价体

单选题囊性纤维变性是一种常染色体遗传病。在欧洲的人群中，每2500个人中就有一人患此病。如一对健康的夫妇有一个患有此病的孩子；此后，该妇女又与一健康的男子再婚。再婚的双亲生一孩子患该病的机会是多少?( )

单选题在细菌转录中，使RNA聚合酶与DNA启动子牢固结合的关键因子是 a．α2； b．ββ′； c．α2ββ′； d．σ(sigma)。

单选题外耳道多毛症是一种遗传病，父亲是患者，则儿子全是患者，女儿全正常。此遗传病基因是( )。

单选题When an invention is made, the inventor has three possible (1) of action open to him: he can give the invention to the world by publishing it, keep the idea (2) , or patent it. A (3) patent is the result of a bargain (4) between an inventor and the state, hut the inventor gets a limited period of monopoly and publishes full details of his invention to the public after that period (5) . Only in the most exceptional circumstances (6) the lifespan of a patent (7) to alter this normal process of events. The longest extension ever (8) was to Georges Valensi; his 1939 patent for color TV receiver circuit was extended until 1971 because for most of the patent's normal life there was no color TV to (9) and thus no hope for reward for the invention. Because a patent remains permanently (10) after it has terminated, the shelves of the library attached to the (11) office contain details of literally millions of ideas that are free for anyone to use and, if (12) than half a century, sometimes even repatent. Indeed, patent experts often advise anyone (13) to avoid the high cost of conducting a search through (14) patents that the one sure way of violation of any other inventor's right is to plagiarize a dead patent. Likewise, because publication of an idea in any other form (15) invalidates further patents on that idea, it is traditionally (16) to take ideas from other areas of print. Much modern technological advance is (17) on these presumptions of legal security. Anyone closely (8) in patents and inventions soon learns that most "new" ideas are, in fact, as old as the hills. It is theft reduction to commercial practice, either through necessity or dedication, or through the availability of new technology, (19) makes news and money. The basic patent for the theory for magnetic recording dates back to 1886. Many of the original ideas behind television originate (20) the late 19th and early 20th century. Even the Volkswagen rear engine ear was anticipated by a 1904 patent for a cart with the horse at the rear.

单选题某植物体细胞内只有一套染色体，所以他是______。 A.单价体 B.单体 C.缺体 D.一倍体

单选题两对基因杂合体F 1 (AaBb)自交后代重组型等于亲组型的遗传是( )。

单选题利用一种Hfr菌株和其对应的F-菌株进行中断杂交试验，结果如图所示，图中列出了a、b、c、d、e、f6个位点的转移数，纵轴表示位点的重组率，横轴表示接合的时间，从这些资料看，Hfr菌株的连锁图是______

单选题当细菌核糖体亚基在CsCl介质中进行离心时，30S和50S亚基分别变为23S和42S亚基，这是由于除去了某些成分所致，被除去的成分是 a．16S rRNA； b．23S rRNA； c．16S rRNA+23S rRNA； d．蛋白质。

单选题在一个有性生殖的自然种群中，除了具有种群大、没有突变发生、没有新基因加入以及个体间的交配是随机的以外，还需具备下列哪一条件，种群的基因库是稳定的( )。

单选题在真核细胞中tRNA的转录是为 a．RNA pol Ⅰ工负责的； b．RNA pol Ⅱ负责的； c．RNA pol Ⅲ负责的； d．不由任何RNA pol负责。

单选题两个植物自交系，它们的种子重量分别为0.2kg和0.4kg，杂交得到的F1种子为0.3kg，F1×F1杂交产生了1024个植株，4株为0.2kg重的种子，4株为0.4kg重的种子，其他植株的种子重量则介于二者中间，由此可估计决定种子重量的基因约为( )对。

单选题用达尔文的自然选择学说，来判断下列叙述中正确的是( )。

单选题两个植物杂交，它们的种子质量分别是0.02kg，杂交得到的F1代的种子都是0.03kg，自交得1000个植株，4株0.018kg的种子，4株是0.04kg，其他植株的种子质量在这两个极端值之间，那么决定种子质量的基因有( )对。

单选题European farm ministers have ended three weeks of negotiations with a deal which they claim represents genuine reform of the common agricultural policy (CAP). Will it be enough to kick off the Doha world trade negotiations? On the face of it, the deal agreed in the early hours of Thursday June 26th looks promising. Most subsidies linked to specific farm products are, at last, to be broken--the idea is to replace these with a direct payment to farmers, .unconnected to particular products. Support prices for several key products, including milk and butter, are to be cut-that should mean European prices eventually falling towards the world market level. Cut-ting the link between subsidy and production was the main objective of proposals put forward by Mr. Fischler, which had formed the starting point for the negotiations. The CAP is hugely unpopular around the world. It subsidizes European farmers to such an extent that they can undercut farmers from poor countries, who also face trade barriers that largely exclude them from the potentially lucrative European market. Farm trade is also a key feature of the Doha round of trade talks, launched under the auspices of the World Trade Organization (WTO) in November 2001. Developing countries have lined up alongside a number of industrial countries to demand an end to the massive subsidies Europe pays its farmers. Several Doha deadlines have already been missed because of the EU's intransigence, and the survival of the talks will be at risk if no progress is made by September, when the world's trade ministers meet in Cancun, Mexico. But now even the French seem to have gone along with the deal hammered out in Luxembourg. Up to a point, anyway. The package of measures gives the green light for the most eager reformers to move fast to implement the changes within their own countries. But there is an escape clause of sorts for the French and other reform-averse nations. They can delay implementation for up to two years. There is also a suggestion that the reforms might not apply where there is a chance that they would lead to a reduction in land under cultivation. These 1et-outs are potentially damaging for Europe's negotiators in the Doha round. They could significantly reduce the cost savings that the reforms might otherwise generate and, in turn, keep European expenditure on farm support unacceptably high by world standards. Mote generally, the escape clauses could undermine the reforms by encouraging the suspicion that the new package will not deliver the changes that its supporters claim Close analysis of what is inevitably a very complicated package might confirm the sceptics' fears.

单选题对于突变与进化的关系，以下哪种说法最正确?( )

单选题Sanger的双脱氧末端终止法DNA序列测定中不需要下列哪种物质?______

单选题Horse thieves, cattle rustlers, bank robbers, train and stagecoach robbers, highwaymen, murderers, these were but some of the criminals who infested the American frontier during the 19th century. In English legend Robin Hood can be considered a bandit, but the outlaws of the Old West were far more violent men and women without any scruples when it came to taking property or life. The careers of many outlaws have been glamorized through fictional accounts of their deeds and their exploits have been the basis for many movie scripts. The era of the American outlaw lasted about 100 years roughly from 1800 to 1900．There had been lawlessness during the Colonial Era. Frontiers have always attracted misfits, failures and renegades who hope to profit by being beyond the reach of government. In the years just before the Revolutionary War, gangs of horse thieves in the back country of South Carolina were broken up by organized bands of farmers called regulators. As frontier settlement expanded rapidly after the Revolution, more opportunities for criminals opened, two common types of bandits were highwaymen and river pirates. Highwaymen accosted people who traveled on foot or horseback, while river pirates preyed upon the boat traffic on the Ohio, Mississippi, and other rivers. Some bandits engaged in both. Criminals in the West gathered momentum with the gold rushes to California, Idaho, Montana, Nevada, and other states. Stagecoaches and trains carrying gold and money became prime targets for bands of outlaws. Bank robberies emerged after the California Gold Rush of 1849 and as prosperity found its way to frontier towns. The first stage robbery was recorded in 1851, and the first train robbery happened in 1866. After the Civil War there was the growth of the cattle kingdom in Texas and neighboring states. Cattle rustling and horse theft turned into significant operations. Range wars bred a great amount of violence. Cattlemen fought over land and water rights, and they fought with great bitterness against sheep farmers. In Texas, range wars were fought over the use of barbed wire to fence grazing land. By the end of the 19th century, the frontier era was past. Major crime shifted to the cities. Ethnic gangs had existed in the slums for decades, preying mostly on their fellow immigrants. With the arrival of Prohibition in the 1920s, an impetus was given to the formation of organized crime as it exists today.