遗传学上的密码子是指( ) A.DNA一条链上相邻的3个碱基 B.mRNA上决定一个氨基酸的3个相邻碱基 C.tRNA上一端的3个碱基 D.DNA分子上3个相邻的碱基对 答案:解:A、密码子在mRNA上,A错误; B、密码子是mRNA上决定一个氨基酸的3个相邻碱基,B正确; C、密码子在mRNA上,tRNA一端的3个相邻的碱基称为反密码子,C错误; D、密码子在mRNA上,D错误. 故选:B.
My mum dropped me off at elementary school, leaving me alone to ________ new challenges.
[ ]
A.
offer
B.
avoid
C.
deal with
D.
face with