A horizontal bar chart displays the top 10 countries by population for 2020. Each bar is rendered as an SVG rect, with its length proportional to the population value on a linear scale. The chart uses D3 v5 scales (d3.scaleBand and d3.scaleLinear) for positioning and sizing, while React components structure the axes and marks. Data is loaded asynchronously from a CSV file via d3.csv, and tick labels are formatted using d3.format with a custom abbreviation for billions.