豌豆的种群中，亲代中AA基因型个体占30％，aa基因型个体占20％，则亲代A的基因频率和F1中AA的基因型频率分别是：（）_刷题宝

题干

豌豆的种群中，亲代中AA基因型个体占30％，aa基因型个体占20％，则亲代A的基因频率和F₁中AA的基因型频率分别是：（）

A：55％和42.5％

B：55％和32.5％

C：45％和32.5％

D：45％和42.5％

上一题下一题 0.0难度选择题更新时间:2019-07-11 04:43:58

答案(点此获取答案解析）

B

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Hello

I just joined "English Kids". Feeling bad that I could have found this earlier. Now my son is 4 years old.

He can understand but not started speaking English. What should I do?

Maria

Hi

Thanks for your post. It's never too late to start practicing English with your son! It's great that he ready understands some English, and in his own time he will start to speak. This is certainly a go time to start practicing English with him and I hope that the advice in the article will help.

Don't expect too much too quickly. Children often need a lot of time to take in the language before they begin speaking themselves. The main thing is to be patient, give your son lots of encouragement and to show him that you enjoy speaking English, If you are enthusiastic, he will be too!

I hope that help.

Best wishes.

Jo

Learning English kids team.

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