题干

有一位遗传学家,在实验中发现一种显性致死现象。黄色毛皮的鼠不能纯种传代,但可杂种传代,而灰色皮毛的鼠能够纯种传代,黄鼠和黄鼠交配,其后代黄鼠2896只,灰鼠1235只,那么此交配中致死个体出现的概率为

A:25%

B:33%

C:66.7%

D:75%

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答案(点此获取答案解析)

A

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下面文章中有五处需要添加小标题。请从以下选项(A、B、C、D、E和F)中选出符合各段意思的小标题。选项中有一项是多余选项。

How Can You Create Luck in Everyday Life?

    You can probably agree that some people have more good things happening to them. Let's just call that luck. Now would you like to learn how to be one of these lucky people? Here are 5 top tips for creating your own luck.

    ____   

    It is easy to believe that you never have any luck in everyday life if you don't seem to be getting any breaks. But having had a difficult life gives you unusual lessons and develops courage.

    ____    

    Some people are already lucky and they just don't know it. Instead of giving all your attention to what you are short of, look at how lucky you already are. You no doubt have some wonderful friends family and a roof over your head.

    ____    

    Luck doesn't just happen upon us—it comes to us when we're open. Learning a new skill, visiting a new place and trying a new hobby are all great ways of creating your chances.

    ____      

    You'll never create any luck if you sit there waiting for it to fall into your lap. Take steps towards your goals and dreams and greet every challenge. You will find you create more luck in everyday life.

    ____     

    Sometimes people would be prepared to help us out. If you need a hand with dealing with something rather than wait for someone to offer you a lucky break, go and ask them if they will help you out.

A. Try Something New

B. Take Action Right Now

C. Ask for Help If Necessary

D. Feel Lucky about What You Have

E. See the Good in the Past

F. Be Confident at Any Time