题干

亲代的许多性状之所以在子代身上体现,原因是(  )

A:精子和卵细胞中携带着亲代的性状

B:精子和卵细胞中携带着控制性状的基因

C:总在一起生活,长相就会相像

D:父母所有的性状都遗传给了子代

上一题 下一题 0.0难度 选择题 更新时间:2019-05-20 05:08:59

答案(点此获取答案解析)

B

同类题2

Chris Jones 刚刚结束了一次不寻常的印度之旅,记者就此对他进行了采访。以下是采访的部分内容:

Reporter: ____

Chris: Well, it all started two years ago when I was planning a trip to India, I visited  a photographic(摄影的) exhibition of elephants and I realized that the only way to travel around India was on an elephant.

Reporter: ____

Chris: I flew to New Delhi and started looking for an elephant. I needed an elephant trained to carry people. I asked an expert for help. He taught me how to ride an elephant. He also helped me find an elephant.

Reporter: ____

Chris: Not too long, I bought a female(母的) elephant called Tara for about USD 6, 000.

Reporter: ____

Chris: Tara and I set off from New Delhi a week later. We were heading to Sonepur in northern India. And what a ride! Elephants can travel at about 6 miles an hour and Sonepur was more than 1, 200 km away. It took us 64 days to complete the journey.

Reporter: ____

Chris: Yes, a few. But nothing serious. On the third day, Tara hurt her foot. But that got better quickly. Also, there was a lot of heavy rain during the first week and we got very wet!

请根据Chris Jones 的回答,从A、B、C、D、E、F六个选项中选择恰当的问题填入相应的五个空格中。

A. How long did it take to find a suitable elephant?

B. What gave you the idea to travel around India on an elephant?

C. Did you have any problems on your journey?

D. Can you tell me the journey?

E. What did you do next?

F. An unusual journey.

同类题4

阅读理解

    Soon computers and other machines will be able to remember you by looking at your eyes! The program works because everyone's eyes are different. So in the future you won't have to remember the number of your credit card when you want to use a machine or take money out of a bank. You'll just have to look at the machine and it will be able to tell who you are.

    The eye-recognition(眼睛识别)program has already been tested in shops and banks in the USA, Britain, Spain, Italy and Turkey. Soon this technology will take the place of all other ways of finding out who people are.

    Eye-recognition is a course of recognizing iris(虹膜), which includes the following steps. First, a kind of machine needs to collect different examples of one's iris from his eyes and store them. Second, when this person goes to the bank to take out money, this machine will have iris feature extraction(采集). Then, this machine will compare the examples kept in it with iris feature extraction. Once the examples and the feature extraction are the same, this person will be identified, and he will take out the money from the bank successfully.

    However, scientists are also working on other systems. Machines will soon be able to know you from the shape of your face or hand or even your smell! We already have machines that can tell who you are from your voice or the mark made by your finger.

    Eye-recognition is better than other kinds because your eyes don't change as you get older, and don't get dirty like hands or fingers, and even twins have different eyes. So the eye-recognition program can be up to 94% correct, depending on how good the technology is. However, some other programs may only be 51% correct now. In Britain, it was found that 91% of people who had tried it said that they liked the idea of eye-recognition.

    In the future your computer will be looking you in the eye. So smile!