Define "migration."

Migration is defined as the movement of people from one place to another. This definition encompasses a wide range of movements, including individuals relocating for reasons such as employment, education, family reunification, or escape from adverse conditions, such as conflict or environmental factors. It is a dynamic process that can occur within a country (internal migration) or across national borders (international migration).

The process of migration has significant implications for both the places that people leave and those that they move to, affecting social structures, economies, and cultures. Understanding migration helps in analyzing population trends and patterns, including urbanization and demographic changes. The other options do not accurately capture the essence of migration. National income pertains to economic metrics, population density refers to the distribution of people within an area, and the settling of new agricultural land focuses specifically on land use rather than the broader phenomenon of people relocating.