单选题As with many a grown-up sporting star, the first hint of greatness came at an early age for Lewis Hamilton. As an eight-year-old at his first kart race, he charged "more like a mature driver than a novice," remembers Martin Hines, owner of the Zip Kart racing company. Scything his way through the field just outside London, Hamilton had a confident style that seemed different from normal rookies, Hines says. "There was a little spark about him." Now 22, and in his debut season in Formula One—he became the first black driver to make it onto the grid in motor racing's blue-ribbon championship. His success and profile that have earned young Hamilton comparisons with other sporting greats. His color— Hamilton's grandfather came to Britain from Grenada in the 50s—and the positive influence of his father, Anthony, have drawn parallels with Tiger Woods. Hamilton acknowledges that his participation could stoke interest among ethnic groups who may not be into the sport now. "Hopefully people that can relate to me will see that it's possible and also try to get into the sport," he told the BBC. Moreover, his youth, good looks and wholesome image are also likely to get marketers fired up. Countless more karting titles followed before 2001. He "made seasoned drivers look silly," says Tony Shaw, Hamilton's then team manager at Manor Motorsport. Hamilton's raw, natural speed and canny race craft nudged him closer to the big leagues. Hamilton's "understanding of when and where to overtake and how to take advantage of a situation is very advanced," Shaw says. At his first crack at GP2, the training ground for Formula One, Hamilton dominated the 2006 season with a series of blistering drives on his way to the title. Hamilton is "not worried about showing or doing what he's used to doing just because it's Formula One," says Hill. For many new drivers, "that's an enormous hurdle." With the retirement last year of seven-time world champion Michael Schumacher, there's one less rival for Hamilton to negotiate. And Hamilton is certainly not short on confidence. When he first met Ron Dennis—now his Formula One team boss—as a 10-year-old in a borrowed suit, Hamilton promptly told him he wanted to drive for McLaren. Three years later, he joined the team's support program for promising young drivers. But, say former team managers, he's ready to listen and learn when things go wrong. Hamilton has a rare "capacity to question himself—to analyze very clearly after a race," says Frederic Vasseur, general manager at the ART Grand Prix team behind Hamilton's GP2 championship. As for whether he'll become the Tiger Woods of the sport, it's too early to know whether he can live up to those standards. But for now, his fans are bullish. Damon Hill was the last British driver to take the world crown. And it's Hamilton, Hill says, "who looks likely to be the next./

单选题纯种芦花雄鸡和非芦花母鸡交配，得到的子一代相互交配，子二代(F2)表现：______。 A．1/2芦花(♂)，1/2芦花(♀) B．1/2非芦花(♂)，1/2非芦花(♀) C．3/4芦花(♀♂)，1/4非芦花(♀♂) D．全为芦花(♂)，1/2非芦花(♀)1/2芦花(♀)

单选题两个基因A、B通常相距38cM，却在某生物染色体的同一臂上。在这38cM的区域内，大约有1/3的长度是一个臂内倒位。但这个倒位不包括这两个基因座。如果该植物是臂内倒位杂合子，这两个基因间的重组率如何?______。 A．大于38cM B．等于38cM C．小于38cM D．不能确定

单选题细菌中各种mRNA所编码的蛋白质数目常有差异，据此有monocistronic，polycistronic和intereistronic之分。多数mRNA是 a．monocistronic mRNA； b．polycistronic mRNA； C．intercistronic mRNA。

单选题一个AB血型的男人与一个B血型的女人结婚，生了4个孩子，第一个是AB型，第二个为O型，第三个为AB型，第四个为A型。后来，由于夫妻不和，丈夫提出离婚，声称经血型家系分析，他不可能是所有孩子的父亲，他说的有道理吗?______

单选题将S型细菌杀死，分别分离纯化出DNA、RNA、蛋白质和多糖荚膜，然后混合起来用______处理后与R型活细菌共同感染小鼠，则不出现转化现象，不能引起肺炎。

单选题家猫中有一位于常染色体上的基因杂合时，呈现无尾性状(只在骨盆上有痕迹)，而在纯合体时，又是致死的，那么当一无尾猫与另一无尾猫杂交时，子代表型为______

单选题在一个岛上，1999年的种群中，二倍体植物的等位基因Aa的频率为p(A)=0.90，q(a)=0.10，如假定2000年种群数仅为50，那么2000年失去等位基因a[p(A)=1]的概率是什么?

单选题One of the most important social developments that helped to make possible a shift in thinking about the r01e of public education was the effect of the baby boom of the 1950s and 1960s on the schools. In the 1920s, but especially in the Depression conditions of the 1930s, the United States experienced a declining birth rate—every thousand women aged fifteen to forty-four gave birth to about 118 live children in 1920, 89.2 in 1930, 75.8 in 1936, and 80 in 1940. With the growing prosperity brought on by the Second World War and the economic boom that followed it, young people married and established households earlier and began to raise larger families than had their predecessors during the Depression. Birth rates rose to 102 per thousand in 1946, 106.2 in 1950, and 118 in 1955. Although economics was probably the most important determinant, it is not the only explanation for the baby boom. The increased value placed on the idea of the family also helps to explain this rise in birth rates. The baby boomers began streaming into the first grade by the mid-1940s and became a flood by 1950. The public school system suddenly found itself overtaxed. While the number of schoolchildren rose because of wartime and postwar conditions, these same conditions made the schools even less prepared to cope with the flood. The wartime economy meant that few new schools were built between 1940 and 1945. Moreover, during the war and in the boom times that followed, large numbers of teachers left their profession for better-paying jobs elsewhere in the economy. Therefore, in the 1950s and 1960s, the baby boom hit an antiquated and inadequate school system. Consequently, the "custodial rhetoric" of the 1930s and early 1940s no longer made sense; that is, keeping youths aged sixteen and older out of the labor market by keeping them in school could no longer be a high priority for an institution unable to find space and staff to teach younger children aged five to sixteen. With the baby boom, the focus of educators and of laymen interested in education inevitably turned toward the lower grades and back to basic academic skills and discipline. The system no longer had much interest in offering nontraditional, new, and extra services to older youth.

单选题假定一个座位上有20个复等位基因，那么可能存在的基因型有______。

单选题A commonplace in genetics is the relationship between recombination frequency and crossover value. Generally speaking, ______. A．recombination frequency may be directly obtained according to phenotypic ratios, but crossover value cannot be directly obtained according to phenotypic ratios B．crossover value may be replaced by recombination frequency or chiasm frequency you get from the observation under microscope when genetic distance is considerably short C．crossover value may be replaced by recombination frequency when genetic distance is as a medium value, not too long and not too short D．recombination frequency will be very different from crossover value when there is a third locus in between the two loci you analysed

单选题对一生物减数分裂进行细胞学检查，发现后期Ⅰ出现染色体桥，表明该生物可能含有______。 A．臂间倒位染色体 B．相互易位染色体 C．臂内倒位染色体 D．顶端缺失染色体

单选题序列(IS)编码 ____ 。

单选题在20世纪30年代，对于生物进化过程中遗传和变异的研究，已经从( )。

单选题有人用菜豆作实验材料，用一个有色、大粒品系和另一白色、小粒品系杂交，得到的结果是：有色PP，45株，种子平均质量(0.307±0.05)kg；中间色Pp，80株，种子平均质量(0.283±0.03)kg；白色pp，41株，种子平均质量(0.264±0.05)kg。产生这些差异的可能原因是( )。

单选题以青霉素培养基作为选择培养基，用来筛选细菌的营养缺陷型，这一技术的原理是______。 A．青霉素可杀死敏感型细菌，只允许抗性细菌生存 B．青霉素有时可以补偿营养缺陷型，允许营养缺陷性细菌在基本培养基上生存 C．青霉素在营养缺陷型的菌落特征上，起明显的修饰作用，便于人们观察认识 D．青霉素可杀死繁殖的原养型细菌，只留下营养缺陷型

单选题下列何种杂交可引起λ噬菌体裂解细菌细胞______ A.Hfr(λ)×F- B.Hfr×F-(λ) C.Hfr×F D.Hfr(λ)×F-(λ) E.上述答案都不对

单选题隐性上位发生的情况下，一般在：F2中的表型比为______。 A.9:3:3:1 B.9:3:4 C.15:1 D.9:7

单选题细菌抗药性的提高是由下列哪种原因造成的?( )

单选题That rapscallion who leaps off the monkey bars, landing smack onto an innocent 3-year-old bystander, and skips off, giggling all the while? According to a new paper out of Israel, he may not feel all that bad about the incident. The study, conducted by Dr. In bal Kivenson Bar-On at the University of Haifa, shows that high levels of fearlessness in 3-and 4-year-olds is strongly associated with aggression and a lack of sympathy. This news will likely surprise risk-loving America, where parents typically beam with pride when their undaunted child mounts the big slide. Fearlessness is a far-end point on the spectrum of what psychologists call the "approach and withdrawal dimension"—people's tendency to approach new stimuli (to gain information and acquire new skills ) and withdraw from unfamiliar stimuli (to avoid danger). Striking the right balance is considered crucial to man's survival. But what about preschoolers'? There's a clear downside, Dr. Kivenson Bar-On discovered, after she observed lots of preschool play and machinations. In total, she documented 80 children at preschool, home and in the lab, measuring their propensity for fearlessness and other social and emotional characteristics at the beginning and end of one year. Fearlessness was measured by observing reactions to various fright-inducing situations: separation from parents, the roar of a vacuum cleaner, a jack-in-the-box and the like. Those who displayed greater levels of fearlessness, the study found, had no trouble recognizing facial expressions of anger, surprise, happiness and sadness in other children—but they had a hard time identifying fear. Over all, they were "emotionally shallow" and showed lower levels of sympathy. They took advantage of friends and lacked regret over inappropriate conduct. "These findings," the paper explains, " suggest that fearlessness in preschool constitutes a clear risk factor for developmental pathways that lead to problems in morality, conscience development, and severe antisocial behaviors. " At the same time, fearless children tended to be highly sociable. "One of the most interesting findings was that we could discriminate between friendliness and sympathy," Dr. Kivenson Bar-On said. "These kids are curious, easygoing and friendly, but they have a hard time recognizing emotional distress in others. " Jamie Ostrov, a psychology professor at the State University at Buffalo who studies aggression, says that children at the extreme end of the fearless spectrurn "may be charming, but they're also highly manipulative and deceptive and skilled at getting their way—even at age 3 or 4. " It could be that fearless children need stronger distress cues to active their autonomic nervous systems, limiting their ability to detect distress cues in others. It seems to be, if I'm not worried about this, you can't be, either. But should we be?