适合双子叶植物花药培养的培养基是()。
A.MS培养基
B.B5培养基
C.N6培养基
D.White培养基
参考答案:A
The key to our success was having the courage to take on any job, and then being creative in our _______ to getting it finished.
A.measure
B.approach
C.methods
D.chance
1只雌蛙能产4000粒——5000粒卵,卵受精后只有不足10%的发育成为成体,按照达尔文的观点解释,造成这种现象的主要原因是()
A.过度繁殖
B.生存斗争
C.遗传变异
D.适者生存