In a population of an area, natality was equal to mortality for a given time equal to mortality for a given time period. However, the population density of the population increased, whih of the following may be the reason for the increases ?

Options

A. Number of immigrants = number of emigrants
B. Number of immigrants gt Number of emigrants
C. Number of immigrants lt Number of emigrants
D. Cannot be predicted

Answer

To solve the question regarding the increase in population density despite natality being equal to mortality, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Key Terms**:
- **Natality**: This refers to the birth rate in a population.
- **Mortality**: This refers to the death rate in a population.
- **Population Density**: This is defined as the number of individuals per unit area.

2. **Analyze the Given Information**:
- The question states that natality is equal to mortality (n = m). This means that the number of births is equal to the number of deaths over a specific time period.
- Despite this balance, the population density is increasing.

3. **Consider Possible Reasons for Increased Population Density**:
- Since natality equals mortality, the increase in population density cannot be attributed to natural population growth (births exceeding deaths).
- Therefore, we need to consider immigration and emigration.

4. **Evaluate Immigration and Emigration**:
- **Immigration**: Individuals moving into the population.
- **Emigration**: Individuals moving out of the population.

5. **Assess Each Option**:
- **Option 1**: Number of immigrants equals number of emigrants.
- If this were true, the population density would remain constant, not increase.
- **Option 2**: Number of emigrants is less than the number of immigrants.
- This means more individuals are entering the population than leaving, which would lead to an increase in population density.
- **Option 3**: Number of immigrants is less than the number of emigrants.
- This would lead to a decrease in population density, which contradicts the information given.
- **Option 4**: Cannot be predicted.
- This does not provide a definitive reason for the increase in population density.

6. **Conclusion**:
- The only viable explanation for the increase in population density, given that natality equals mortality, is that the number of immigrants is greater than the number of emigrants. Thus, the correct answer is **Option 2**.