【单选题】真实遗传的弗吉尼亚烟草中,三个显性等位基因分别决定烟草叶子的形态 (M) 、颜色 (C) 和大小 (S) 。卡罗来那烟草这三个基因座上都是隐性纯合的。三个基因座位于同一条染色体上, C 在中央, MC 的图距为 6mu, CS 图距为 17mu 。两种烟草杂交的 F1 代再与卡罗来那烟草回交,回交产生的子代中,三种性状都和卡罗来那烟草相同的占:——
【简答题】He never goes to meetings. He spends most of his time with his customers. He likes his job, but his favourite time of day is about 9:00 in the evening when he finishes work. He usually goes for someth...