What does the author say about women students in college?
A. They have no idea how to bring out their best.
B. They drop a course when they find it too rigorous.
C. They are not as practical as men in choosing courses.
D. They don’t perform as well as they did in high school.
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How does the author explain the pay gap between men and women fresh from college?
A. Women are too worn out to be ambitious.
B. Women are not ready to take management roles.
C. Women are caught between career and family.
D. Women are not good at negotiating salaries.
在核酸中可用于计算核酸含量的元素是:
A. C
B. N
C. O
D. P
E. H
核酸的紫外吸收是由哪一结构所产生的?
A. 嘌呤和嘧啶之间的氢键
B. 碱基和戊糖之间的糖苷键
C. 戊糖和磷酸之间的磷酯键
D. 嘌呤和嘧啶环上的共轭双键
E. 核苷酸之间的磷酸二酯键
关于DNA双螺旋结构模型的叙述,哪一项是错误的?
A. 由两条反向平行的DNA链组成
B. 碱基具有严格的配对关系
C. 戊糖和磷酸组成的骨架在外侧
D. 碱基平面垂直于中心轴
E. 生物细胞中所有DNA二级结构都是右手螺旋
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