Final answer:
The first phase of the health care system's development focused on dealing with epidemics of infectious diseases and improvements in sanitation and public health measures. The acceptance of germ theory and advancements in immunization and antibiotic treatment were key factors in this era.
Step-by-step explanation:
The first phase of development of the health care system was characterized by epidemics of infectious disease, such as typhoid, influenza, and malaria. During this period, which can be traced back to the early 1800s during the public health movement in Britain, there was a major push for improvements in urban sanitation and housing. This era set the stage for advancements in medical science and the development of public health initiatives.
In the 19th century, the germ theory of disease became more widely accepted, propelled by the work of pioneers such as Robert Koch and Louis Pasteur. This led to the systematic study of disease patterns - a field known as epidemiology. As a result, critical innovations such as the development of immunizations for deadly diseases and the widespread use of antibiotics like penicillin occurred, drastically improving life expectancy and public health standards.