Final answer:
At a systems level of practice, a Public Health Nurse would most likely focus on changing laws, policies, and practices that impact population-based issues to create lasting health improvements.
Step-by-step explanation:
A Public Health Nurse (PHN) working at the systems level of practice would most likely engage in interventions that involve systemic change. Among the presented options, the intervention most aligned with this level of practice is to change laws, policies, and practices that influence population-based issues. Systems-level interventions surpass individual care and look towards larger scale changes that impact population health.
This could involve advocating for policies that ensure equitable access to healthcare, creating and promoting public health legislation, or institutional reforms that address social determinants of health. These systemic changes not only address immediate healthcare needs but also work to prevent future health issues by altering the environment in which health decisions are made.