Final answer:
Tsui's statement signifies that historical combat readiness was judged on the bare minimum physical capabilities, such as having enough teeth to handle ammunition and the strength to carry a weapon.
Step-by-step explanation:
When Tsui states, "If you had enough teeth in your head and could hold a musket, you were fine," she is communicating the idea that in the context of battle, particularly in historical times, the criteria for being considered able or fit for combat were very basic. One needed to have the physical capability to bite down on a cartridge, as was necessary to prepare some muskets for firing, and the strength to wield a weapon. This highlights the rudimentary and often desperate requirements for soldiers, which did not take into account their experience, skill, or even overall health as long as they could perform the minimal necessary functions.