What is meant by replacement level with reference to human population growth?

Explanation

### Step-by-Step Solution:

1. **Definition of Replacement Level**:
- The replacement level refers to the fertility rate at which a population exactly replaces itself from one generation to the next. This means that the number of births is equal to the number of deaths over time.

2. **Fertility Rate Requirement**:
- In developed countries, the replacement level fertility is typically around 2.1 children per woman. This figure accounts for the fact that not all children will survive to adulthood, hence the slight increase above 2.

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