33. The primitive streak in a bird is the functional equivalent of__________.
(A) the lip of the blastopore in the frog
(B) the archenteron in a frog
(C) the notochord in a mammal
(D) neural crest cells in a mammal
答案:登入後查看
統計: 尚無統計資料
統計: 尚無統計資料