<prompt> Demographic divided is due to -Increase fertilityDecrease fertilityDecrease in death rateNone  <response>: Demographic windowThe period of time in a nations demographic evolution when the proportion of population of working age group 15-55 years is particularly prominent people 15 years of age are less than 30 and 65 years of age are less than 15.The demographic window opportunity lasts for 30-40 years i.e. from the age of 15 to age of 55.Demographic window of India is expected from 2010 to 2050Demographic dividendA rise in the rate of economic growth due to a rising share of working age people in a population.It occurs when fertility rate falls. Lets see why :-Because of mechanical link between fertility levels and age structure, when the birth rate fertility falls, the age pyramid first shrinks with gradual lower proportion of young population under 15 years and proportion of population in working age group increases. This has following effects -i The respective nation has demographic window.Output per capita rises as population in working age group is prominent and dependency ratio child dependency ratio is decreased.In other words, decrease fertility rate is responsible for demographic dividend and demographic window.Demographic giftThis the gift due to decreased fertility rate.That means favorable effects demographic dividend of decrease in fertility rate.Demographic transitionA model used to explain the process of transition from high birth rate death rate to low birth rate death rate.Demographic trapThis trap is the population growth due to high birth rate and low death rate.Demography bonusThe term demography bonus connotes the period when the dependency ratio in a population declines because of decline in fertility, until it starts to rise again because of increasing longevity.Demographic burdenIt is the increase in the total dependency ratio during any period of time, mostly caused by increased old age dependency ratio. 