`A overset(oplus)to " population density" (N) overset(T)larrB`.
If A increases the population density and B decrases then identify A and B

Options

A. A-natality B-mortality
B. A-immigration B-emigration
C. both 1 and 2
D. A-emigration,B-immigration

Answer

To solve the question regarding the factors that affect population density, we need to identify two components: A, which increases population density, and B, which decreases it.

### Step-by-Step Solution:

1. **Understanding Population Density**:
- Population density (N) refers to the number of individuals of a species per unit area or volume.

2. **Identifying Factors that Increase Population Density (A)**:
- **Natality**: This is the birth rate, which refers to the number of births in a population over a specific period. An increase in natality leads to an increase in population density.
- **I-Migration**: This refers to the influx of individuals from other areas into the habitat. When individuals move into a population, it increases the population density.

3. **Identifying Factors that Decrease Population Density (B)**:
- **Mortality**: This is the death rate, which refers to the number of deaths in a population over a specific period. An increase in mortality results in a decrease in population density.
- **E-Migration**: This refers to the outflow of individuals from the population to other areas. When individuals leave the population, it decreases the population density.

4. **Conclusion**:
- Thus, we can identify:
- A = Natality or I-Migration (both increase population density)
- B = Mortality or E-Migration (both decrease population density)

### Final Answer:
- A can be either **Natality** or **I-Migration** (both increase population density).
- B can be either **Mortality** or **E-Migration** (both decrease population density).