Exam OG0-091 topic 1 question 75 discussion

https://pubs.opengroup.org/architecture/togaf9-doc/arch/chap33.html A building block is a package of functionality defined to meet the business needs across an organization. A building block has a type that corresponds to the enterprise's content metamodel (such as actor, business service, application, or data entity). A building block has a defined boundary and is generally recognizable as "a thing" by domain experts. A building block may interoperate with other, inter-dependent building blocks. A good building block has the following characteristics: It considers implementation and usage, and evolves to exploit technology and standards. It may be assembled from other building blocks. It may be a subassembly of other building blocks. Ideally a building block is re-usable and replaceable, and well specified. A building block's boundary and specification should be loosely coupled to its implementation; i.e., it should be possible to realize a building block in several different ways without impacting the boundary or specification of the building block

not always a software could be an infrastructure etc.