Population density of a population in a given hanitat during a given period fluctuates due to change in

Options

A. natality and mortality
B. immiigration
C. emigration
D. all of these

Answer

To answer the question regarding the fluctuation of population density in a given habitat during a specific period, we need to consider several key factors that influence population dynamics. Here's a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understanding Population Density**:
- Population density refers to the number of individuals of a species per unit area in a specific habitat. It can change over time due to various biological and environmental factors.

2. **Identifying Key Factors**:
- The primary factors that can cause fluctuations in population density are:
- **Natality**: This refers to the birth rate within the population. An increase in natality will lead to a higher population density.
- **Mortality**: This is the death rate in the population. An increase in mortality will decrease the population density.
- **I-migration**: This is the movement of individuals into a population from other areas. I-migration increases the population density as new individuals join the habitat.
- **E-migration**: This is the movement of individuals out of a population to other areas. E-migration decreases the population density as individuals leave the habitat.

3. **Analyzing the Effects of Each Factor**:
- **Natality**: Higher birth rates contribute positively to population density.
- **Mortality**: Higher death rates contribute negatively to population density.
- **I-migration**: The arrival of new individuals increases population density.
- **E-migration**: The departure of individuals decreases population density.

4. **Conclusion**:
- All these factors (natality, mortality, I-migration, and E-migration) collectively influence the population density in a habitat. Therefore, the population density fluctuates due to changes in all of these factors.

5. **Final Answer**:
- The correct answer to the question is: "All of these" factors cause fluctuations in population density.