Which of the following is considered a controllable risk factor for disease?

Smoking is considered a controllable risk factor for disease because it is a behavior that individuals can modify or quit. Unlike genetics, age, and some environmental factors, which may be beyond an individual's control, smoking is a personal choice that significantly impacts health. By choosing not to smoke or by quitting, individuals can reduce their risk of developing various diseases, such as lung cancer, cardiovascular disease, and respiratory illnesses. This ability to influence health outcomes through lifestyle changes is what categorizes smoking as a controllable risk factor.