Final answer:
Public health has transitioned from focusing on modern medicine and health services to preventive measures and behavioral changes.
Step-by-step explanation:
The transition in public health has occurred from primarily focusing on introducing modern medicine and health services to the population to primarily emphasizing preventive measures and behavioral changes.
Initially, public health officials taught hygienic practices to mothers and encouraged behavioral changes such as reducing smoking. Government funding was directed towards public sanitation systems and research, leading to advancements in medicine. Later, the focus shifted towards clean water and waste disposal systems, changes in public behavior, and advancements in medicine through the development of immunizations for diseases like diphtheria.
This transition reflects a shift in public health strategies from primarily reactive measures to proactive measures.