This example displays a stacked bar chart of the Iris dataset, showing the cumulative contributions of sepal and petal measurements for each of the three species. It uses D3 v7 to load the CSV data with `d3.csv`, then applies the `d3.stack()` function to create series for the four attributes. The visualization renders as SVG, with axes and a legend constructed using `d3.axisBottom`, `d3.axisLeft`, and a custom legend group.