Regarding the type and distribution of RNA, which of the following statements is correct（）
A. RNA is mainly found in the nucleus
B. mRNA accounts for about 5% of the total RNA of the cell and serves as a template in protein synthesis
C. rRNA accounts for 80% of the total RNA of the cell, is a component of the ribosome, and is a place for protein synthesis
D. tRNA accounts for 10-15% of the total RNA of the cell, and plays the role of carrying activated amino acids in protein synthesis
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The secondary structure of DNA refers to（）
A. α-helix
B. β-sheet
C. β-turn
Double helix structure
After the complete hydrolysis of DNA and RNA, the characteristics of its products are（）
A. Different pentoses and different bases
B. Different pentoses and the same bases
C. The same pentose and the same base
D. The same pentose and different base
通常情况下，下列选项中不能用于启动Word的操作是（）
A. 单击Windows桌面上的Word快捷方式图标
B. 双击Windows桌面上的Word快捷方式图标
C. 单击”开始”→”所有程序”→”Microsoft Office”→”Microsoft Word”
D. 在Windows资源管理器中双击Word文档图标
我国最常见的非缺失型α地贫的突变是（）
A. Constant Spring（CS）
B. 右侧缺失（-α3.7）
C. QuongSze（QS）
D. 左侧缺失（-α4.2）
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