题目

阅读理解 One day a rich boy bought a magic mirror (镜子). When he got home, he looked in the mirror. His face looked sad. He tried to smile and make funny faces, his face looked still sad. Then he did many happy things, but his face always looked sad. “Oh, what a terrible mirror! It doesn’t work! ” he said angrily. The next day on his way to buy some chocolate, he saw a little girl crying sadly. The rich boy went up to her and asked what had happened. The little girl said she couldn’t find her parents. “Don’t worry. I’ll help you,” the rich boy said. So they went 生物体在产生后代过程中会产生一些新的类型，运用不同生物学原理适当的选育，即可培育出各种符合人类需要的生物品种。下列关于育种的说法中正确的是： A.三倍体西瓜植株联会紊乱，无法产生正常的配子，因此该变异属于不可遗传的变异 B.培育矮秆抗病小麦，可用杂交育种或单倍体育种的方法，二者相比前者简便后者快捷 C.多倍体育种与单倍体育种都要用到秋水仙素，其中后者得到的品种植株矮小且不育 D.纯种高杆抗病利用ｒ射线照射培育出的矮杆抗病品种，特点是周期短，容易获得