The software architecture of a program or computing system is the structure or structures of the system, which comprise software ______, the externally ______properties of those components, and the relationships between them.The architecture is not the operational software. Rather, it is a ______ that enables a software engineer to: analyze the ______ of the design in meeting its stated requirements, consider architectural alternatives at a stage when making design changes is still relatively easy, and reduce the ______ associated with the construction of the software.

A. qualityB. budget C. schedules D. risks

染色单体的形成消失分别发生在细胞周期中的（）

A.前期、后期

B.间期、末期

C.间期、后期

D.前期、末期