The population having the same number of individuals in the pre-reproductive and post-reproductive age is called a steady population.

A steady population refers to a population in which the number of individuals in the pre-reproductive age (those who are too young to reproduce) is equal to the number of individuals in the post-reproductive age (those who have passed their reproductive age). This means that the population is neither growing nor declining, as the number of individuals entering the reproductive age is balanced by the number of individuals leaving the reproductive age.

This concept is important in understanding population dynamics and demographic trends. It provides insights into the age structure of a population and its potential for growth or decline. A steady population is often associated with developed countries where the birth rate is low and the life expectancy is high.

Here are some key points to further explain the concept of a steady population:

1. Age structure: A steady population has a balanced age structure, with a relatively equal number of individuals in each age group.

2. Birth rate and death rate: In a steady population, the birth rate is equal to the death rate, resulting in zero population growth. This is often observed in countries with low fertility rates and low mortality rates.

3. Replacement level fertility: A steady population can be sustained when each couple has, on average, two children. This is known as replacement level fertility, where each parent replaces themselves and the partner, maintaining a stable population size.

4. Population stability: A steady population indicates a certain level of population stability, as it suggests that the population is maintaining a relatively constant size over time.

5. Implications: A steady population poses challenges and opportunities for a country's social and economic development. It may face issues such as an aging population, a smaller workforce, and increased healthcare and pension costs. However, it can also provide opportunities for improving the quality of life and focusing on sustainable development.

In conclusion, a population with the same number of individuals in the pre-reproductive and post-reproductive age is referred to as a steady population. It indicates a balanced age structure and suggests that the population is neither growing nor declining. Understanding the dynamics of a steady population is crucial for effective planning and resource allocation in various sectors, including healthcare, education, and social welfare.