题目

阅读理解 TadatoyoYamamoto is a Japanese businessman. He visits the U.S. from time to time. While he was telephoning at a hotel on a visit to Chicago, he put his bag on the floor. A few minutes later, Mr. Tadatoyo Yamamoto reached down for it, but it was gone. Inside it were about ＄900, his passport, photos of his family, and his return ticket to Japan. But three weeks after he returned to Tokyo, Mr. Tadatoyo Yamamoto received an envelope. There was nothing inside but his passport.His airline ticket and money order(汇票)for more than＄900 and a letter from Mr. Joseph Loveras. I变异是生物的基本特征之一，下列不属于细菌产生的可遗传变异有（  ）①基因突变  ②基因重组 ③染色体变异 ④环境条件的变化 ⑤染色单体互换⑥非同源染色体上非等位基因自由组合A．①②③ B．④⑤⑥ C．②③④⑤⑥ D．①②③④