出入细胞的方式中，简单扩散(自由扩散)区别于协助扩散的是

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='21274' and id < 1848516 and id<>'1848516' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='21274' and id > 1848516 and id<>'1848516' order by id asc limit 5