Final answer:
The 20th century witnessed significant health improvements that contributed to longer life expectancy and better living conditions due to medical innovations, better hygiene practices, and public health infrastructure. However, these advancements were not uniformly distributed across the globe, and the health sector faced a setback in the 1980s with the emergence of HIV/AIDS.
Step-by-step explanation:
The 20th century was remarkable for significant health improvements that largely contributed to a revolution in the human condition. These advances were pivotal in increasing the quality and life expectancy of the world's population. A noteworthy increase in health was due to the implementation of public health infrastructure, such as systems for clean water and sanitation that reduced disease transmission. Public behavior changes also played a critical role, including hygiene practices and reduced tobacco use. However, the crux of health advancements lay in medical innovations; the creation of vaccines for diseases like diphtheria, cholera, and pertussis, and the discovery of antibiotics, including penicillin. These medical advances had a profound effect, curtailing infectious diseases and reducing the mortality rate.
Despite these medical leaps, the distribution of health improvements didn't occur uniformly. While Western Europe and its associated nations initially led these advancements, other less developed regions began to 'catch up,' with areas like sub-Saharan Africa gaining traction later in the century. The global oil boom also affected health improvements, notably in oil-producing countries.