Explanation:

The demographic gap refers to the difference between the birth rate and the death rate in a specific population. It is also known as the population growth rate. The demographic gap is a significant factor in determining the size and composition of a population over time.

Factors affecting the demographic gap:

1. Fertility Rate: The number of children born to women is the primary factor that influences the birth rate. In countries with high fertility rates, the demographic gap tends to be large, leading to a younger population.

2. Mortality Rate: The number of deaths in a population is another factor that affects the demographic gap. In countries with high mortality rates, the demographic gap tends to be smaller, leading to an older population.

3. Immigration and Emigration: The movement of people into and out of a population can also affect the demographic gap. Immigration can increase the birth rate and overall population size, while emigration can decrease it.

Impact of demographic gap:

1. Ageing Population: A smaller demographic gap can lead to an ageing population, as the number of births is not high enough to replace the number of deaths.

2. Economic Implications: A larger demographic gap can lead to a larger working-age population, which can have economic benefits.

3. Social Implications: The demographic gap can also impact social factors such as education, healthcare, and housing.

Conclusion:

The demographic gap is an important factor in understanding population growth and composition. It is affected by various factors such as fertility rate, mortality rate, and migration. The impact of the demographic gap can be significant on economic, social, and political factors.