A horizontal bar chart displays population estimates for ten countries, with each rectangle’s height fixed at 300 pixels and width also fixed at 300 pixels, so the bars do not encode the values proportionally. The data from `data.csv` is loaded via `d3.csv`, and each population value is multiplied by 1000 in JavaScript to convert units. The chart is rendered as an SVG, using `d3.select` to target the `<svg>` element and `svg.selectAll('rect').data().enter()` to append rectangles.