What is the key concept for this section? What is the age structure of a population? Explain how age structure affects population growth and economic growth. What is demographic momentum? Describe the...

What is the key concept for this section? What is the age structure of a population? Explain how age structure affects population growth and economic growth. What is demographic momentum? Describe the baby boom in the United States and some of its economic and social effects. What are some problems related to rapid population decline due to an aging population?