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, which of the following may be the reason for the increases ?

Options

A. Number of immigrants = number of emigrants
B. Number of immigrants greater Number of emigrants
C. Number of immigrants lesser 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 break down the problem step by step:

### Step 1: Understand the Definitions
- **Natality** refers to the birth rate in a population, which is the number of births per unit time.
- **Mortality** refers to the death rate in a population, which is the number of deaths per unit time.

### Step 2: Analyze the Given Condition
- The question states that natality is equal to mortality. This means that the number of individuals being born is equal to the number of individuals dying. Therefore, there should be no net increase in the population size based solely on births and deaths.

### Step 3: Consider Other Factors
- Since the population density is increasing despite natality equaling mortality, we need to consider other factors that could contribute to this increase. One significant factor is migration.

### Step 4: Understand Migration
- **Immigration** refers to individuals entering a population from outside, while **Emigration** refers to individuals leaving the population to go elsewhere.
- If the number of immigrants (individuals entering) is greater than the number of emigrants (individuals leaving), this would result in an increase in the overall population density.

### Step 5: Evaluate the Options
- The options provided in the question likely relate to the balance between immigration and emigration:
1. Number of immigrants equals number of emigrants (no change in population).
2. Number of immigrants greater than number of emigrants (population increases).
3. Number of immigrants less than number of emigrants (population decreases).
4. Cannot be predicted (not applicable).

### Conclusion
- The correct answer is that the number of immigrants is greater than the number of emigrants, which would lead to an increase in population density.

### Final Answer
**The increase in population density is due to the number of immigrants being greater than the number of emigrants.**

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