题目

 According to the regulations of our company, everybody is to be taken on for a three-month trial period before being accepted as a ____ member of staff．ks5u A. temporary                B. instant              C. permanent                D. consistent 答案：C蜗牛的有条纹(A)对无条纹(a)为显性。现一生物兴趣小组将两只有条纹的蜗牛杂交(交配),后代出现了无条纹的蜗牛。则亲代蜗牛的基因组成分别是　(　　)A.AA、Aa　　??? ????????????? B.Aa、Aa　　???? ????????????? C.Aa、aa　???? 　????????????? D.AA、aa