Final answer:
Advancements in public sanitation, changes in public behavior, and developments in medicine have contributed to the changing understanding of health over time.
Step-by-step explanation:
The understanding of health has changed over time due to various factors. Firstly, advancements in public sanitation and hygiene practices, such as clean water supply and waste disposal systems, have helped to prevent the transmission of diseases. Secondly, changes in public behavior, such as the adoption of handwashing practices and reducing smoking rates, have contributed to better health outcomes. Lastly, advancements in medicine, including the development of immunizations and treatments for various diseases, have significantly improved healthcare.