If birth and death rates were equal, a zero population growth rate would result. It is known as

Options

A. Replacement level
B. Rate of natural increase
C. Stable population
D. Doubling time

Answer

To solve the question regarding the condition where birth and death rates are equal resulting in a zero population growth rate, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Zero Population Growth (ZPG)**:
- Zero Population Growth occurs when the number of births equals the number of deaths in a population over a certain period. This means that the overall population size remains stable.

2. **Identifying Key Terms**:
- The term "replacement level" refers to the number of children that need to be born to replace the population, which is typically around 2.1 children per woman in developed countries. However, this does not directly define zero population growth.

3. **Evaluating Options**:
- **Replacement Level**: This is related to fertility rates but does not directly define the condition of zero population growth.
- **Rate of Natural Increase**: This refers to the difference between the birth rate and death rate. If they are equal, the rate of natural increase is zero, which aligns with zero population growth.
- **Doubling Time**: This is the time required for a population to double in size, which is not relevant to the concept of zero population growth.

4. **Conclusion**:
- The correct term for the condition where birth and death rates are equal, leading to zero population growth, is known as the "demographic equilibrium" or "stable population." This indicates that the population is neither increasing nor decreasing.

### Final Answer:
The condition where birth and death rates are equal, resulting in a zero population growth rate, is known as **demographic equilibrium**.