单选题纯种芦花雄鸡和非芦花母鸡交配，得到子一代。子一代个体互相交配，问子二代的芦花性状与性别的关系是 ____ 。

单选题λ噬菌体侵入大肠杆菌细胞后通过______而进入溶原状态。

单选题现代生物进化论认为：种群是生物进化的基本单位；突变、选择和隔离是新物种形成的基本环节。其中新物种形成的必要条件是( )。

单选题在一个E. coli细胞中同时存在两个lac操纵子，其中一个的操纵基因为野生型(Oo)，另一个的操纵基因为组成突变型(Oc)，则 a．由于Oc的存在，Oo不起作用，即不再结合阻抑物； b．由于Oo的存在，Oc无效，即含Oc的操纵子；也不能结合阻抑物； c．两个操纵子互不影响。

单选题 Vienna was one of the music centers of Europe during the classical period, and Haydn, Mozart, and Beethoven were all active there. As the (1) of the Holy Roman Empire (which included parts of present-day Austria, Germany, Italy, Hungary, Czech and Slovakia), it was a (2) cultural and commercial center (3) a cosmopolitan character. Its population of almost 250,000 (in 1800) made Vienna the fourth largest city in Europe. All three (4) masters were born elsewhere, but they were (5) to Vienna to study and to seek (6) . In Vienna, Haydn and Mozart became close friends and influenced each other's musical (7) . Beethoven traveled to Vienna at sixteen to play for Mozart; at twenty-two, he returned to study with Haydn. Aristocrats from all over the Empire spent the winter in Vienna, sometimes bringing their private (8) . Music was an important part of court life, and a good orchestra was a (9) of prestige. Many of the nobility were excellent musicians. Much music was heard in (10) concerts where aristocrats and wealthy commoners played (11) professional musicians. Mozart and Beethoven often earned money by performing in these intimate concerts. The nobility (12) hired servants who could (13) as musicians. An advertisement in the Vienna Gazette of 1789 (14) : " Wanted, for a house of the gentry, a manservant who knows how to play the violin well. " In Vienna there was also (15) music, light and popular in (16) . Small street bands of wind and string players played at garden parties or under the windows of people (17) to throw (18) money. Haydn and Mozart wrote many outdoor entertainment (19) , (20) they called divertimentos or serenades. Vienna's great love of music and its enthusiastic demand for new works made it the chosen city of Haydn, Mozart and Beethoven.

单选题两种噬菌体杂交，如a+b+×a-b-，下列哪种公式可用于计算位点间的重组率______ A．a+b-/(a+b++a+b-) B．a-b+/(a+b++a-b+) C．(a+b-+a-b+)/(a+b-+a-b++a+b+) D．(a+b-+a-b+)/(a+b-+a-b++a+b++a-b-) E．上述答案均不对

单选题"I was just like you--I' thought I was invincible," says Adam Blomberg, standing before 400 students in a darkened auditorium at Miami's Coral Reef Senior High School. A photo of a bloodied and unconscious teenager, a breathing tube protruding from his mouth, flashes on the wall. "That was me," he says. There's a collective gasp before the room grows silent and Blomberg,31, an anesthesiologist who trained at Brigham and Women's Hospital in Boston, begins the story of what happened one night in February 1995. He created a presentation illustrating the dangers of behaving irresponsibly in a car, from not buckling up to speeding to driving under the influence of alcohol and drugs. He tracked down photos of teen crash victims from the center's archives, then incorporated statistics and his own experience. He spoke the first time to a local Boy Scout troop and was soon giving his talk, "A Survivor's Story," at high schools around the state. The Blomberg family had reason to celebrate. Adam had fully recovered and was on his way to fulfilling his lifelong dream of becoming a doctor. But in January 2000, Blomberg's 22-year-old step-brother, Michael, was killed in a crash while driving to his Atlanta home late one night. He wasn't wearing a seat belt. After the accident, Blomberg stopped telling his story to crowds, racked with guilt over his inability to reach Michael. If Blomberg had failed his own brother, he reasoned, how could he possibly make a difference to a roomful of strangers? Requests from schools continued to roll in, but he turned down every one. Then Blomberg got a call from a high school counselor. As he started into his standard excuse-lack of time—he looked across the room at a stack of thank-you notes from students who had heard him speak. He realized that kids needed to hear what he had to say. He agreed to visit the school and began contacting others on the waiting list for his talks. Blomberg leaves the school hoping he has changed someone's behavior. He recalls a letter he received from a student who heard him speak and got into a crash later that same day but was unharmed. " She told me she was wearing her seat belt because of me." Letters like this reinforce his belief that he survived the accident for a reason. "There are a lot of physicians in the world, and we all save lives," he says. "I have a special opportunity to save lives not just as a doctor but also as a human being./

单选题已知人类中，棕色眼(B)对蓝色眼(b)为显性，棕色眼与蓝色眼的人结婚，生下的第一个孩子是蓝色眼，则棕色眼人的基因型是______。 A．bb B．BB C．Bb D．无法确定

单选题我国的杂交水稻主要是在袁隆平教授的主持下研究成功。他提出了通过选育水稻______，利用水稻的杂种优势，打破了“水稻等自花授粉作物没有杂种优势”的传统观念，丰富了遗传育种理论和技术，具有很高的学术价值。 A．雄性不育系、雄性不育保持系、雄性不育恢复系的三系法途径。 B．雄性不育系、雄性可育系、雄性不育保持系的三系法途径。 C．雄性不育系、雄性可育系的二系法途径。 D．雄性不育保持系、雄性不育恢复系的二系法途径。

单选题下列性别畸形个体的体内相对不含雄性激素的是( )。

单选题以下哪种情况不属于同源重组?( )

单选题某些转座过程中( )是作为一种中间体存在的。

单选题雄鹿往往用鹿角作为争夺配偶的武器，所以它的鹿角发达。按达尔文的观点，鹿角发达的原因是( )。

单选题以青霉素培养基做为选择培养基，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，只允许抗性型细菌在上生存 B．青霉素有时可补偿营养缺陷型，允许营养缺陷型细菌在基本培养上生存 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。