题目

用马铃薯的花药离体培养出的单倍体植株，可以正常地进行减数分裂，用显微镜可以观察到染色体两两配对形成12对。据此现象可推知产生该花药的马铃薯是( )A. 三倍体 B. 二倍体 C. 四倍体 D. 六倍体 答案：【答案】C【解析】试题用花药离体培养法可以得到单倍体，单倍体的体细胞中含有本物种配子染色体数目。根据题干信息“单倍体植株进行减数分裂时，染色体两两配对形成12对”可知该单倍体细胞中含有两个染色体组，据此推知产生花药的马铃薯的体细胞中含有四个染色体组。故选C第二节完形填空(共20小题，每小题1分，满分20分)阅读下面短文，掌握其大意，然后从36—55各题所给的四个选项(A、B、C和D)中选出最佳选项，并在答题卡上将该项涂黑。 A gentle breeze blew through Jennifer’s hair．The golden red sun was  36 She was on thebeach，looking up at the fiery ball．She could hear nothing but the waves and the  37  flying upin the sky． The  38   relaxed her．After all she’had been through，this is what she needed． She wondered how her parents would  39 ，when she got home after the three days she was missing．She kept on walking，  40  herself-to bungalow 163，where’she spent every summer holiday．Just in a few hundred meters she would have been  4 1  in her house． It was really getting dark now ,the sun had set a few minutes before and it was getting  42 too．She imagined having her favorite  43  on：it kept her really warm．This thought   44 when she finally saw her front door．45 had taken care of the outside garden for a few days．She was  46 ：her father was usually so strict about keeping everything clean and tidy,and now.. It all seemed  47 ：．She couldn’t understand what was  48  on． She entered the house．First．she went into the kitchen where she saw a(n)  49  written by her father,reading“'Dear Ellen,there is some coffee ready,1 went looking．”Ellen was her mother but where was she?On the right side ofthe hallway was her parents  50  She went in．Then shesaw her．Her motther lying on the bed,sleeping．Her face looked so tired，  51   she hadn’t slept for days．Jenny would have wanted to wake her up，but she didn’t  52  her tired mother．So Jenny just fell asleep  53    her．When Jennifer woke up something was different…she wasn’t in her mother’s room．She was in her cozy bed in her pajamas． It  54  so good being back home．Suddenly she heard a voice，‘'Are you feeling better now,dear?You now you got us very,very  55 ．”36．A．rising        B．setting         C．shining         D．1anding37．A．seagulls      B．angels         C．parrots          D．rainbows38．A．condition     B．style           C．atmosphere      D．weather39．A．resist        B．reflect          C．reject           D．react40．A．directing     B．assisting         C．allowing        D．commanding41．A．tired        B．thrilled          C．safe            D．anxious42．A．hot         B．warm           C．cloudy           D．cold43．A．cap        B．sweater         C．slippers          D．jewelry44．A．aroused     B．fipeaed           C．disappeared      D．formed45．A．Nobody    B．Somebody       C．Everybody       D．Anybody46．A．terrifled    B．shoeked         C．excimd          D．disturbed47．A．declined    B．deployed         C．designed         D．deserted48．A．going      B．marching          C．coming         D．taking49．A．e-mail     B．composition        C．1etter           D．note50．A．study      B．bed               C．room           D．balcony51．A．in that     B．asif               C．now that         D．even if52．A．force      B．comfort           C．interrupt          D．blame53．A．around     B．beneath           C．beside            D．over54．A．sounded    B．1ooked           C．seemed           D．felt55．A．annoyed    B．scared           C．confused          D．embarrassed