A:on which arc located
B:where is located
C:which locate
D:which are located
右图中圈表示磷酸基,五边形代表示五碳糖,长方形代表一种碱基,那么个图表示的分子是
如图是家鸽体内部分结构分布示意图,图中3所示的结构名称是( )