下列实例中种群基因频率未发生变化的是_刷题宝

题干

下列实例中种群基因频率未发生变化的是（）

A：在黑褐色环境中黑色桦尺蠖被保留，浅色桦尺蠖被淘汰

B：杂合高茎豌豆通过连续自交导致后代纯合子比例越来越高

C：杂交育种过程中通过不断自交、筛选提高纯合矮秆抗病小麦的比例

D：通过辐射青霉菌获得青霉素高产菌株

上一题下一题 0.0难度选择题更新时间:2017-03-15 06:01:13

答案(点此获取答案解析）

B

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如图,在4×4的正方形网格中,△MNP绕某点旋转一定的角度,得到△M₁N₁P₁,则其旋转中心可能是( )

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