What is 'age composition'? How does it affect the population's

What is ‘age composition’? How does it affect the population’s social and economic structure?

The age composition of a population refers to the number of people in different age groups in a country. It affects the population’s social and economic structure because
(i) Children (0-14 years)do not contribute to the economy in any way, they require resources for their health, education, etc.
(ii) Adults (15-60 years) contribute to the nation’s economy by earning money. They are the working population as they feed and look after die two age groups.
(iii) Aged (60 + years) do not contribute to the economy in any way. They depend on the adults. However, sometimes, people belonging to this age group do work but it is for private agencies as they are not considered for recruitment after that age.