牙发育时,成釉器下方的球形细胞凝集区将形成
A. 牙板
B. 牙乳头
C. 牙釉质
D. 牙囊
E. 牙骨质
If you don't put the cheese in the refrigerator it may ().
A. go off
B. go out
C. go over
D. go wrong
While serving in the Senate in the early 1970s Barbara Jordan supported legislation to ban discrimination and to deal with environment problems.
A. list
B. forbid
C. handle
D. investigate
体内氨基酸代谢库中的氨基酸参与下列哪些代谢活动
A. 嘌呤碱的合成
B. 嘧啶碱的合成
C. 血红蛋白的合成
D. 糖异生作用
E. 以上都对