A simple but essential architectural style used in high-quality architecture involves the separation of the  （ ）  building blocks, according to the tenets of Quasar (Quality-Driven Software Architecture). Business building blocks are those that  （ ）  source code for the application domain, such as business rules, calculations, validations, and so on. Technical building blocks solve purely  （ ）  problems, such as database connections, user interfaces, and so on. The basic principle of this architectural style is that each building block contained in an architecture may only be responsible for either of these two aspects. This separation is postulated by Quasar because the domain and technical aspects of software systems usually have very different change cycles. If this separation can be maintained, the result will be a  （ ）  system.

This Quasar-based idea became manageable with the introduction of “blood types” for software components. I think this model has not really become established because the blood-type analogy for software is pretty  （ ） . Nevertheless, this style provides some very important hints that should be obvious to every software architect.