This example displays a horizontal bar chart of population data for 20 countries in 2010, using a green fill for each bar and blue tick marks along the axes. React components render SVG rectangles scaled by D3's `scaleLinear` and `scaleBand` APIs, with axis ticks generated from `xScale.ticks()`. The data is loaded asynchronously from a CSV file via D3's `csv` function, and the population values are reformatted to billions using D3's `format` function, which is also used for tooltips on each bar.