骨髓增生极度活跃,有核细胞与成熟红细胞的比例为()
A.2:5
B.1:4
C.1:1
D.1:10
E.1:50
参考答案:C
N-S diagram can used to substitute conventional program flow Chart.In the following phrases,Which does not belong to the basic control structures that contain
A.sequence structure
B.condition Structure
C.selection structure
D.execution structure
简述人工创造园林植物多倍体和单倍体的方法。