How must an unbalanced condition of an airship be overcome if it is either light or heavy?

The correct answer indicates that an unbalanced condition of an airship can be overcome aerodynamically. When an airship is either too light or heavy, it affects its ability to maintain stable flight. An aerodynamically balanced airship can be controlled by adjusting the aerodynamic surfaces, such as the rudder and elevator, which help to maintain desired flight paths and attitudes.

Aerodynamic adjustments can include changes in pitch and yaw to achieve the desired lift and control the descent or ascent of the airship. By manipulating the ailerons, elevators, and rudders, the pilot can fine-tune the aircraft's response to external forces, allowing for corrections in balance despite the weight or buoyancy issues.

In contrast, simply reducing speed does not effectively address the fundamental issue of the airship's unbalance since a lower speed may not provide sufficient lift or might lead to a stall. Adjusting the gas quantity could help in fine-tuning buoyancy but might not correct all aspects of unbalance on its own. Manual control adjustments can aid in managing the balance in conjunction with aerodynamics but should be seen as a part of the broader aerodynamic management approach rather than a standalone solution.