

A formalized, modern architecture (highest level of system design) helps establish guidelines, patterns, and constraints according to which the code grows.
It helps developers understand and predetermine how a system will work.
iOS app architecture is programmed for security and has customized BSD kernel to program all their libraries from scratch.
Higher layers of architecture provide the user interface and sophisticated graphics while the lower layers in iOS provide the basic services.
These help de-clutter the code, make it more organized and results in loosely coupled applications, easy to change/scalable modules, less likely of bug attack.
These are directories that hold a dynamic shared library like .a files, related resources like header files, images, and helper apps required to support that library.






