This stacked bar chart visualizes the distribution of four flower measurements—sepal length, sepal width, petal length, and petal width—across the three Iris species. Each horizontal bar represents a species, with segments proportional to the percentage of each measurement type. Hovering over a segment reveals the exact percentage via a D3 tooltip. The chart uses `d3.csv` to load the Iris dataset, `d3.stack` for stacking, and `d3.scaleBand` for the y-axis, with data rendered as SVG rectangles.