Final answer:
The focus on health during this century has shifted to all aspects except the boom of oil-producing countries.
Step-by-step explanation:
The focus on health during this century has shifted to all aspects except the boom of the oil-producing countries. Throughout the years, there have been significant advances in medical science and public health measures that have contributed to improving health. These include the development of immunizations, improvements in sanitation and hygiene practices, and changes in public behavior.