Problems related to population:1.Rapid population growth(mainly in less developed countries)2.Ageing populations(mainly in rich societies) 3.Effects of large-scale migration4.Coexistence in a multicultural world.Emigration:refers to people leaving one place to another. Immigration:refers to people arriving from another territory.3 factors of migration:1.Nature:forced or voluntary.2.Duration:temporary or permanent.3.Place:internal or international.Why do people migrate: 1.Economic:especially to employment.2.Social:better quality of life or to be near to the family.3.Political:escaping from conflicts such as wars. 4.Enviromental:escaping from natural disasters:earthquakes or floods. Effects of migration:(in countries of origin)positive:1.It reduces employment pressure.2. Emigrants usually send money home. Negative:1.Families are broken up. 2.The age structure of population changes.3.Highly skilled people tend to migrate.(In destination countries)positive:1.The young population and the bird rate increase.2. Immigrants work contributes to economic growth.3.The number of taxpayers increases.4.Cultural enrichment occurs.Negative:1increased preassure on healthcare.2.Poor living conditions.3.Conflicts many arise between immigrants and the host society.Fundamentalism:are religious movements wich strictly apply the content of sacred texts to regulate the life of a society.How is development measured?The UN created the HDI to determine how advanceda country.Economic contrasts:Unequal distribution of wealth: the GDP is often used to measure a country's economic development.Internal inequalities and extreme pover: the GDP per capita is a good indicator of the wealth a country's inhabitants. Factors that cause underdevelopment:1. The colonial legacy.2.The technologycal gap.3. External debt.4.Population.Overcoming underdevelopment:Less developed countries receive foreign aid from 3 main sources:international organizations,rich countries and NGOs. 1.International organizations:member states of the International Monetary found provide money for loans to countries with economic difficulties.2.Aid from a rich country:rich countries contribute with the 0.7% of their gross national income.3.Aid through NGOs:this are private nonprofit organizations.