A bar chart displays the populations of ten countries in 2020, loaded from a CSV file with D3 utilities. The example integrates React state management with D3 scales to render SVG rectangles, using `scaleBand` for the categorical y-axis and `scaleLinear` for the continuous x-axis. Data is fetched via `d3.csv`, parsed, and stored with React's `useState` and `useEffect`. The visualization updates declaratively through React's rendering, with SVG coordinates computed from D3 scale functions.