Structural strength and stability

Buildings and any other structural element or component thereof shall be designed and constructed to provide acceptable strength and stability, for the structure's lifetime, following accepted building standards and good practice.

In your understanding what is the basic purpose of foundations $($substructures$),$ Floors, stairways, walls $($Superstructures$),$ and Roofs which codes guide them during the design and construction phase and why? $(25$ points$)$