玉米2n=20，易位杂合体在减数分裂中形成二价体的数目为____。
A．11 个
B．10 个
C．9 个
D．8 个
参考答案：D
阅读理解。
1. Xiang Jingyu was born in _____.
A. Xupu county
B. Huitong county
C. Chenxi county
2. Which of the following is True?
A. September 14 is Xiang Jingyu's Birthday.
B. Xiang Jingyu joined CPC in 1922.
C. She was killed at the age of thirty.
中枢性降压药是
A．卡维地洛B．硝普钠C．普萘洛尔D．胍乙啶E．甲基多巴
