Which wing design provides its required strength through a covering that resists flight stresses?

The monocoque design is characterized by its structural efficiency, where the skin of the aircraft acts as a primary load-bearing component. In this approach, the aircraft's strength is derived from a continuous outer shell that can withstand aerodynamic forces and stresses experienced during flight. This allows for a reduction in the number of internal supports or frames, leading to a lighter overall structure.

In contrast, a truss design relies on a framework of beams and struts, which are rigidly connected and carry loads primarily through tension and compression. This design is sturdy but typically heavier and less aerodynamic than a monocoque design.

The semimonocoque design, while similar to a monocoque, uses a combination of the outer skin and internal structures (like stringers and formers) to provide additional strength. It offers improved load distribution compared to pure monocoque but does not fully encompass the unique characteristics of a monocoque structure.

A hydraulic system pertains to the means of controlling flight surfaces and does not contribute to the structural integrity needed to withstand flight stresses. Thus, the monocoque design stands out as the correct answer, given its reliance on the skin to provide necessary strength against flight loads.