What physiological factors influence vital capacity?

Vital capacity, which is the maximum amount of air a person can expel from their lungs after maximum inhalation, is influenced by several physiological factors. Height plays a significant role because taller individuals generally have larger lung volumes due to a bigger thoracic cavity. Sex differences also influence vital capacity, as males typically have larger lung volumes than females, attributed to differences in body size and lung development. Age is crucial as well because vital capacity can decrease with age due to decreased elasticity of lung tissue and weakened respiratory muscles.

Posture affects lung capacity too; for instance, sitting up straight can facilitate better lung expansion than slouching. The strength of respiratory muscles is another important factor; stronger muscles can generate more force for deeper inhalation and stronger exhalation, thus contributing to a greater vital capacity.

While age and height are indeed important, they do not encompass the full range of physiological factors that impact vital capacity, making the answer that includes height, sex, age, posture, and strength of respiratory muscles the most comprehensive and correct choice.