Among the options provided, the risk factor that you can control is:
- Your friends have recently started smoking.
While you cannot change family history or genetic predispositions, you can make choices about the company you keep and whether or not to engage in smoking behaviors influenced by your friends. The other options describe factors (family history and ethnic group incidence) that are beyond your control, and while unintentional accidents are a significant risk, you cannot directly control the risk factor itself without specific actions to mitigate accident risks.