Which one of the following is incorrect for the biogenesis of eukaryotic ribosomes( )

A．25-50% of the pre-rRNA is degraded

B． Pre-rRNA binds to ribosomal protein

C． Pre-rRNA is cut to form three classes of rRNA

D．Pre-rRNA is methylated

E．The rRNA gene for the 40S subunit is transcribed separately

无规则型构型系统可靠性高，但是结构复杂。为了实现正确的传输必须采用( )。
Ⅰ．异步传输技术
Ⅱ．路由选择算法
Ⅲ．流量控制技术
Ⅳ．加密解密技术

A．Ⅰ和Ⅱ

B．Ⅰ和Ⅲ

C．Ⅱ和Ⅲ

D．Ⅱ和Ⅳ