Uneven development creates differences between countries. Advanced countries (ACs) have a lot of money and so they have the power to make decisions that affect low income developing countries (LIDCs).
Many LIDCs have a shortage of safe, clean water and have low levels of health. They do not have factories or processing facilities and so they have to sell materials in their raw form. Raw materials usually sell for much less money than finished products and so these countries earn less. Some governments in LIDCs are corrupt. This means that money earned is not necessarily used to benefit the people that need it and disparities in wealth and health occur. Some LIDCs also have high levels of international migration, as people move to find work and a better standard of living. This results in fewer people of a working age and an increased proportion of dependent people.
ACs have good, clean water supplies and sanitation systems. They are able to buy raw materials for a low price and process them into a more expensive product. Their imports cost less money than their exports and so they have a good balance of trade. They are able to become wealthier as a result. ACs usually have stable governments and so any money earned is used to benefit the people in the country, so fewer disparities in wealth and health occur.