What does a monocoque fuselage design utilize for its strength?

A monocoque fuselage design primarily derives its strength from the skin or outer shell itself, which is designed to bear the structural loads. In this context, utilizing bulkheads, stringers, and formers is integral to its structural integrity.

Bulkheads provide vertical support and act as partitions that help maintain the shape of the fuselage while adding rigidity. Stringers are longitudinal members that run along the length of the fuselage, distributing loads and reinforcing the fuselage's overall strength. Formers, which are cross-sectional members, help maintain the fuselage's shape and provide additional support at key points. Together, these components work in concert with the outer skin to create a lightweight yet strong structure essential for the aircraft's performance and safety.

The other options do not accurately describe how a monocoque design achieves its strength—solid metal sheets would limit the design's overall structure, wooden structures and fabric are characteristic of older aircraft designs, and steel tubing alone does not reflect the monocoque structure for modern aircraft.