依据基因重组概念的发展,判断下列图示过程中没有发生基因重组的是[ ]
A.
B.
C.
D.
答案:A
Betty shows great interest in this poem now, but she thought it boring she read it.
A.at the first time
B.the first time
C.for the first time
D.at first
经验权数法的优点与缺点?