This example demonstrates a React-based bar chart of country populations using D3 for data loading and SVG for rendering. The code uses React’s `useEffect` and `useRef` hooks to fetch a CSV file via `d3.csv`, parse the population values, and append green rectangles as bars. Although the bars are initially rendered as static SVG elements from a mapped array, the effect attempts to update their height and width using D3 selections, but the dependency array on `[m]` may cause rendering inconsistencies. The visualization includes a text label and a 960×500 SVG canvas.