He went to school by car this morning.
A:drive a car to school
B:went to school in a car
C:took a bus to school
D:by car to school
根据如图所示关系回答问题:
胰岛素由____分泌,可以调节____在人体内的吸收、利用和转化过程.
在基因工程的操作过程中,获得重组质粒不需要( )①DNA连接酶 ②同一种限制酶 ③RNA聚合酶 ④具有标记基因的质粒⑤目的基因 ⑥4种脱氧核苷酸