This area chart visualizes life expectancy in the United States over time, using a smooth, filled curve to show the trend. The D3 code (v5) loads data from a CSV file and uses `scaleTime` and `scaleLinear` for the axes, `area` with `curveBasis` to generate the smooth area path, and `axisBottom` and `axisLeft` for gridlines and labels. The title and axis labels are added as SVG text elements.