题干

人类的秃顶基因位于常染色体上,表现型如图所示。一对夫妇中,妻子非秃顶,妻子的母亲秃顶;丈夫秃顶,丈夫的父亲非秃顶。则这对夫妇所生的一个女孩秃顶的概率和秃顶男孩的概率分别为(    )

BB

Bb

bb

非秃顶

秃顶

秃顶

非秃顶

非秃顶

秃顶

A:1/4;3/8

B:1/4;3/4

C:1/8;3/8

D:1/8;3/4

上一题 下一题 0.0难度 选择题 更新时间:2019-10-04 07:01:31

答案(点此获取答案解析)

A

同类题3

阅读上栏中几个人物的信息,从下栏中选出与之相对应或他们最感兴趣的信息。其中有一项为多余选项。

____I'm Grace from the USA. I like singing very much and I am good at it. I want to join a music club.

____I am Anna. I am twenty-seven years old. I can sing and dance. I can also speak English very well. Now I want to find a new job.

____I am Tom. I often get up at half past six every morning, but these days, I often get up late. It usually makes my teachers angry. What should I do?

____I am Zhang Jian from Shandong Province. I like animals very much. My father says he will take me to a zoo this weekend. But we don't know where to go.

____My parents are very strict with me in my study. I have to do my homework and I can't watch TV or listen to music on school days. I don't have any fun.

A. Welcome to the Red Star Zoo. There are many kinds of animals in it. Take your children here. And you can enjoy half price on weekends. I'm sure you'll have a good time.

B. I think you should buy a clock. Put it on your desk. It can wake you up (叫醒你) in the morning. Or you can ask you parents to wake you up. And you also should go to bed early at night.

C. As a student, you have to study hard. Maybe you can talk with them. You can tell them you should relax after doing your homework on school days.

D. We need a teacher who can sing and dance. If you can speak English, it is better. Please call

Joy at 780-4362.

E. I think you should brush your teeth twice (两次) a day. It is good for your health. If you don't do that, your teeth will be bad.

F. Hi, boys and girls. Please come here and join the music club. In the club, you can learn popular songs, listen to them and make some new friends. Please call Jack Smith at 567-0429.

同类题4

阅读理解

    Proudly reading my words, I glanced around the room, only to find my classmates bearing big smiles on their faces and tears in their eyes. Confused, I glanced toward my stone-faced teacher. Having no choice, I slowly raised the report I had slaved over, hoping to hide myself. “What could be causing everyone to act this way?”

    Quickly, I flashed back to the day Miss Lancelot gave me the task. This was the first real talk I received in my new school. It seemed simple: go on the Internet and find information about a man named George Washington. Since my idea of history came from an ancient teacher in my home country, I had never heard of that name before. As I searched the name of this fellow, it became evident that there were two people bearing the same name who looked completely different! One invented hundreds of uses for peanuts, while the other led some sort of army across America. I stared at the screen, wondering which one my teacher meant. I called my grandfather for a golden piece of advice; flip (掷) a coin. Heads—the commander, and tails—the peanuts guy. Ah! Tails, my report would be about the great man who invented peanut butter, George Washington Carver.

    Weeks later, standing before this unfriendly mass, I was totally lost. Oh well, I lowered the paper and sat down at my desk, burning to find out what I had done wrong. As a classmate began his report, it all became clear, “My report is on George Washington, the man who started the American Revolution.” The whole world became quite! How could I know that she meant that George Washington?

    Obviously, my grade was awful. Heartbroken but fearless, I decided to turn this around. I talked to Miss Lancelot, but she insisted: No re-dos; no new grade. I felt that the punishment was not justified, and I believed I deserved a second chance. Consequently, I threw myself heartily into my work for the rest of the school year. Ten months later, that chance unfolded as I found myself sitting in the headmaster's office with my grandfather, now having an entirely different conversation. I smiled and flashed back to the embarrassing moment at the beginning of the year as the headmaster informed me of my option to skip the sixth grade. Justice is sweet!