Buildings, like humans, need air, water, and energy, and to eliminate waste, to function properly. Knowing how to integrate building systems into a project design is a fundamental competency for architects to make sure buildings can properly function.
Isn't the point of design to meet project requirements? This might be the most basic competency of all of them. Your client, or you, have a goal for what you want to achieve for a project. Create a design solution that meets that goal. However, within the seeming simplicity of this competency lies the real challenge.