Final answer:
True, mortality in adult years is often affected by earlier lifestyle choices linked to chronic diseases. It's also true that infant mortality rate and life expectancy are key health indicators for a nation, reflecting health care quality and socioeconomic factors.
Step-by-step explanation:
Mortality during adult years is significantly influenced by lifestyle choices made earlier in life, which can include poor health behaviors contributing to chronic diseases. Thus, this statement is generally true. As for the assertion that infant mortality rate and life expectancy are important indicators of a nation's health, this is also true. These statistics provide insight into the overall health and wealth of nations; higher infant mortality rates and lower life expectancies often correlate with poorer healthcare systems and lower socioeconomic status.
Throughout different stages of societal development, as defined by demographic transition theory, these indicators change. Initially, both infant mortality and general death rates are high with low life expectancy. As a country develops, health care improves, and with industrialization, infant mortality rates drop and life expectancies rise. In advanced stages of development, both rates decrease further, and life expectancy continues to increase.
Furthermore, differences in health outcomes such as life expectancy can arise from personal health choices. This includes diet, exercise, substance consumption, and health care expenditures, making it challenging to differentiate the impact of lifestyle choices from the quality of health care received.