1. (2023高二上·东港开学考) 以下表格表示遗传信息传递中涉及的部分碱基序列，通过分析，你认为mRNA（或密码子）的碱基序列是（ ）                                                                                                                                                                                     

DNA	“链”	A	T	G
	β链
mRNA
tRNA		U