**Explanation:**

The division of the population into rural and urban is primarily based on **residence**. This categorization is used to differentiate and classify the population based on their living environment and location.

**1. Rural Areas:**

Rural areas are characterized by less population density, agricultural activities, and natural landscapes. These areas are typically located outside of cities and towns and are characterized by open spaces, fields, farms, and villages. The majority of the population in rural areas is engaged in agriculture, farming, and other traditional occupations. The infrastructure in rural areas is often less developed compared to urban areas, with limited access to amenities and services.

**2. Urban Areas:**

Urban areas, on the other hand, are characterized by higher population density, industrialization, and urban infrastructure. These areas encompass cities, towns, and densely populated regions. Urban areas are centers of economic, social, and cultural activities, with a concentration of industries, businesses, educational institutions, healthcare facilities, and other services. Urban dwellers are often engaged in non-agricultural professions, such as manufacturing, commerce, services, and technology.

**Reasons for the Division:**

The division of the population into rural and urban is based on several factors, including:

1. **Economic Activities:** Rural areas are primarily engaged in agriculture and farming, while urban areas are centers of industrial, commercial, and service-oriented economic activities.

2. **Infrastructure:** Urban areas have better-developed infrastructure, including transportation networks, communication facilities, healthcare systems, educational institutions, and housing complexes. Rural areas often lack these facilities or have limited access to them.

3. **Population Density:** Urban areas have higher population density compared to rural areas due to the concentration of people in cities and towns.

4. **Amenities and Services:** Urban areas offer a wider range of amenities and services, such as shopping centers, entertainment venues, public transportation, and specialized healthcare facilities.

5. **Social and Cultural Differences:** Rural and urban areas often have distinct social and cultural characteristics. Rural areas tend to have a close-knit community and traditional values, while urban areas are more diverse and cosmopolitan.

6. **Environmental Factors:** Rural areas are often characterized by natural landscapes, farmland, and open spaces, while urban areas have a more built-up environment with skyscrapers, roads, and concrete structures.

In conclusion, the division of the population into rural and urban is primarily determined by their place of residence. This categorization helps in understanding the differences in economic activities, infrastructure, population density, amenities, and social dynamics between rural and urban areas.