Final answer:
Women tend to outnumber men starting in the mid-thirties due to longer life spans and lower mortality rates. Menopause leads to physiological changes that affect women's health, while men have higher death rates from health issues and violence.
Step-by-step explanation:
Biological factors play a role in why women begin to outnumber men in the population starting in the mid-thirties. One of the key biological elements is the difference in life expectancy between the sexes. Women generally live longer than men, which becomes increasingly evident with age. By the time individuals reach middle adulthood, men start to have higher death rates due to factors like heart disease, lung disease, and violence. Moreover, women go through menopause around the age of 50, which leads to a loss of fertility and other significant physiological changes, such as a decrease in bone density due to lower estrogen levels.
Beyond the biological differences, societal factors also affect the gender ratio. For example, social roles and government policies have historically disadvantaged elderly women, often leading to poorer health outcomes. Nevertheless, these gender disparities in healthcare treatment and social security benefits do not directly influence the numerical gender imbalance that is rooted in biological longevity and mortality rates. Lastly, cultural influences and economic opportunities may lead men and women to reside in different parts of the country, further skewing the sex ratio in certain regions.