The correct option is 2 only.
Explanation
Population growth refers to the change in the number of inhabitants of a territory during a specific period. This change is expressed either in absolute numbers or as a percentage. Growth can be positive (increase) or negative (decrease) depending on the interplay of birth rates, death rates, and migration.
Statement-wise Analysis:
- Statement 1 is Incorrect: Negative growth does not occur only when the birth rate falls below the death rate. While a natural decrease (deaths exceeding births) is a major factor, population growth is also determined by migration. Even if the birth rate is higher than the death rate, a population can experience negative growth if net emigration is sufficiently high.
- Statement 2 is Correct: Negative growth can occur if people migrate to other countries (emigration). If the number of people leaving a country exceeds the number of people entering (immigration) and the natural increase (births minus deaths), the total population will decline.
- Statement 3 is Incorrect: A situation where the population remains constant between two points of time represents zero population growth. Negative growth specifically refers to a condition where the total population decreases between two points of time.
Key Takeaway:
Negative growth of population is defined as a decrease in the total population between two time points. It is caused when the sum of natural increase (Births - Deaths) and net migration (Immigration - Emigration) results in a negative value.