下列有关染色体、DNA和基因关系的叙述，错误的是（　　）

A．DNA位于染色体上

B．一条染色体含有一个DNA分子

C．基因是DNA分子上有遗传效应的片段

D．染色体是由DNA和基因组成

Virtualization is an approach to IT that pools and shares（71）so that utilization is optimized and supplies automatically meet demand．Traditional IT environments are often silos, where both technology and human（72）。 are aligned around an application or business function．With a virtualized （73），people, processes, and technology are focused on meeting service levels, （74） is allocated dynamically, resources are optimized, and the entire infrastructure is simplified and flexible．We offer a broad spectrum of virtualization（75）that allows customers to choose the most appropriate path and optimization focus for their IT infrastructure resources．

75（）

A．solutions

B．networks

C．interfaces

D．connections