What are [blanks] cut in rib sections and other structural parts designed to do?

The correct choice highlights that the purpose of cuts in rib sections and other structural parts is primarily to decrease weight. Aircraft design is heavily influenced by the need for structures that are lightweight yet strong enough to withstand various stresses. By incorporating cuts or openings in rib sections, engineers can remove excess material without compromising the structural integrity of the aircraft. This reduction in weight is crucial, as it directly impacts fuel efficiency, payload capacity, and overall performance of the aircraft.

While other options address important aspects of aircraft design and functionality, they do not directly pertain to the primary intent of cuts in rib sections and structural components. For instance, reducing vibration and enhancing strength are considerations in overall aircraft design, but they do not specifically explain the function of these cuts. Similarly, improving aerodynamics is essential for aircraft efficiency, yet the cuts themselves primarily focus on lowering weight rather than enhancing the aerodynamic profile.