题目

白绵羊与白绵羊交配，后代出现了白绵羊和黑绵羊，产生这种现象的根本原因是( ) A．姐妹染色单体分离  B．等位基因分离 C．基因重组                     D．性状分离   答案：BCan you describe ________?A.what the student look likeB.what does the student look likeC.what does the student looks likeD.what the student looks like