The document discusses population structure and how it can be analyzed using population pyramids. It explains that population structure looks at a country's population grouped by age and sex. Interpreting population pyramids involves looking at recent birth rates at the base, life expectancy at the top, and any prominent age groups in the middle. A country's dependency ratio is also linked to its population structure and economic activity. The document then analyzes how the UK's population structure has changed over time from 1841-1981, with fewer children and an aging population. Lastly, it compares population pyramids between more and less economically developed countries.