某一生物有四对染色体，假设一个精母细胞在产生精细胞的过程中，其中一个初级精母细胞在分裂后期有一对染色体移向了同一极，则这个精母细胞产生正常精细胞和异常精细胞的比例为[ ]

A．1：1

B．1：2

C．1：3

D．0：4

MIMD systems can be classified into (1) -oriented systems, high-availability systems and response-oriented systems. The goal of (1) -oriented multiprocessing is to obtain high
(1) (2) minimal computing cost. The techniques employed by multiprocessor operating systems to achieve this goal take advantage of an inherent processing versus input/output balance in the workload to produce (3) and (4) loading of system (5)

A．resource

B．resources

C．source

D．sources