The correct option is It occurs when the birth rate is higher than the death rate or when people migrate into a region..
Explanation
Population growth refers to the change in the number of inhabitants of a territory during a specific period. This change can be positive or negative. It is influenced by three primary components: birth rate, death rate, and migration.
Analysis of Positive Growth:
Positive growth of population occurs when the total population increases between two points in time. This happens under the following conditions:
- Natural Increase: When the birth rate is higher than the death rate, the population naturally expands.
- Migration (Induced Growth): When people migrate into a region (in-migration) from other countries or regions, adding to the existing population.
Therefore, positive growth is not restricted to natural increase alone but also includes population gains through migration.
Option Analysis:
- It occurs only when the birth rate exceeds the death rate. is incorrect: While a higher birth rate leads to growth, it is not the only cause; migration is also a factor.
- It occurs only when there is permanent in-migration from other countries. is incorrect: In-migration causes growth, but natural increase (births exceeding deaths) is also a major cause.
- It occurs when the death rate exceeds the birth rate. is incorrect: When the death rate exceeds the birth rate, it typically leads to a negative growth of population (population decline), assuming net migration does not offset it.
- It occurs when the birth rate is higher than the death rate or when people migrate into a region. is correct: It correctly identifies that positive growth occurs either when the birth rate exceeds the death rate or when people migrate into a region.
Key Takeaway:
Positive population growth is driven by Natural Increase (Births > Deaths) and Net In-migration. Conversely, negative growth occurs if birth rates fall below death rates or through net out-migration.