A:who
B:which
C:why
D:whe
赤道地区( )
Judging from the message they convey, these two chapters are __________ independent of each other, that is, they are not in connection with the other at all.
①检测生物组织中还原糖 ②检测生物组织中的脂肪 ③检测生物组织中的蛋白质 ④观察DNA和RNA在细胞中的分布 ⑤用高倍镜观察叶绿体 ⑥用高倍镜观察线粒体 ⑦体验制备细胞膜的方法