A：哺乳动物成熟的红细胞无线粒体一定不能进行细胞呼吸
B：自然界生物体内所有细胞中核糖体的形成都与核仁密切相关
C：细菌细胞中存在既含有蛋白质又含有核酸的结构
D：洋葱的根尖细胞中无叶绿体，所以用根尖细胞不能培养出含叶绿体的植物体
Our lessons
We have Chinese，Maths，English and Science on Monday morning．In the afternoon，we have PE and Music．On Tuesday morning we have Maths，English，Chinese and Art．In the afternoon，we have Science and Music．On Wednesday morning，we have English，Chinese，Maths and History(历史).In the afternoon，we have Computer and Art．
Weekdays
Monday
Tuesday
Wednesday
In the morning
Chinese
____
English
Maths
In the afternoon
Science
Computer
Music
物质
铜
银
金
密度g/cm3
8.9
10.5
19.3
