Which of the following factors has a negative effect on the population growth rate ?

Options

A. Emigration
B. Immigration
C. Natality
D. Fecundity

Explanation

To determine which factor has a negative effect on the population growth rate, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a factor that negatively impacts the population growth rate. This means we are looking for something that decreases the number of individuals in a population.

2. **Analyze Emigration**:
- Emigration refers to the permanent outward movement of individuals from a population to settle in a new area.
- When individuals leave a population, the total number of individuals in that population decreases.
- Therefore, emigration has a negative effect on the population growth rate.

3. **Analyze Immigration**:
- Immigration is the permanent inward movement of individuals into a population.
- This movement increases the number of individuals in the population.
- Hence, immigration has a positive effect on the population growth rate.

4. **Analyze Natality**:
- Natality refers to the birth rate within a population.
- An increase in birth rates leads to more individuals being added to the population.
- Thus, natality has a positive effect on the population growth rate.

5. **Analyze Fecundity**:
- Fecundity is the ability of an organism to produce offspring.
- Higher fecundity means more offspring are produced, which contributes to an increase in population size.
- Therefore, fecundity also has a positive effect on the population growth rate.

6. **Conclusion**: After analyzing all the options, the only factor that has a negative effect on the population growth rate is **emigration**.

### Final Answer:
The factor that has a negative effect on the population growth rate is **emigration**.

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