【单选题】We most often think of communication as talking, but it commonly occurs in other forms as well. In addition to words, communication can occur in the form. of pictures or through actions. When we speak...
【单选题】用一野生型菌株抽提出来的 DNA 片段来转化一个不能合成丙氨酸( ala )脯氨酸( pro )和精氨酸( arg )的突变型菌株,产生不同转化类型菌落数如下: 转化类型 菌落数 ala + pro + arg + 8400 ala + pro - arg + 2100 ala - pro + arg + 420 ala - pro - arg + 840 ala + pro - arg - 84...