Define 'zero population growth rate'. Draw a age pyramid for the same.

Explanation

### Step-by-Step Solution

1. **Definition of Zero Population Growth Rate**:
- Zero population growth rate (ZPG) refers to a situation where the number of individuals in a population remains constant over time. This occurs when the birth rate plus immigration equals the death rate plus emigration, resulting in no net change in population size. In terms of age distribution, this is characterized by a balanced number of individuals in the pre-reproductive, reproductive, and post-reproductive age groups.

2. **Characteristics of Age Distribution**:
- In a population with zero population growth, the age pyramid will show a relatively equal distribution across different age groups. The pre-reproductive age group (typically ages 0-14) will have a smaller number of individuals compared to the reproductive (ages 15-49) and post-reproductive age groups (ages 50 and above). This results in a stable population where the number of births is approximately equal to the number of deaths.

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