Why does life expectancy vary across the world?

Life expectancy varies across the world due to a combination of factors, including healthcare access, economic stability, nutrition, and education. Countries with robust healthcare systems, higher income levels, and better education typically have longer life expectancies. Additionally, social determinants such as living conditions, environmental factors, and public health policies play significant roles in influencing overall health outcomes. Diseases, conflicts, and lifestyle choices also contribute to disparities in life expectancy between regions.