Changing population is -

Options

A. Population growth
B. Population dynamics
C. Population explosion
D. Population ethology

Answer

### Step-by-Step Solution:

1. **Understanding the Concept of Population Change**:
- Population change refers to the variation in the number of individuals in a population over a specific period of time. This can be influenced by various factors such as birth rates, death rates, immigration, and emigration.

2. **Factors Influencing Population Change**:
- **Birth Rate**: The number of births in a population over a specific time period contributes positively to population growth.
- **Death Rate**: The number of deaths in a population over a specific time period contributes negatively to population growth.
- **Immigration**: The arrival of individuals from outside the population can increase the population size.
- **Emigration**: The departure of individuals from the population can decrease the population size.

3. **Calculating Population Change**:
- To determine the change in population over a year, we can use the formula:
\[ \text{Population Change} = \text{Population at End of Year} - \text{Population at Start of Year} = Y - X \]
- Here, \(X\) is the population at the beginning of the year and \(Y\) is the population at the end of the year.

4. **Possible Outcomes of Population Change**:
- The population can either:
- Increase (due to high birth rates and immigration)
- Decrease (due to high death rates and emigration)
- Remain constant (when the number of births equals the number of deaths, and immigration equals emigration)

5. **Conclusion**:
- The term that encompasses all these changes in population over time is referred to as **population dynamics**. Therefore, the correct answer to the question "What is the changing population?" is **population dynamics**.