A:汞、镉等有毒物质
B:二氧化碳
C:沙尘暴
D:氟利昂
若要在普通显微镜下观察到质壁分离、RNA和脂肪,下列四组材料中应选择的一组是( )
The naughty boy is always in his room.His mother is very angry.