This stacked bar chart shows the average measurements of sepal length, width, petal length, and width for three iris species (setosa, versicolor, and virginica), with each bar segment colored by feature type. The visualization uses d3.stack to aggregate the data, d3.scaleLinear for the horizontal axis, and d3.scaleBand for the vertical species categories. Hovering over any segment reveals a tooltip with the precise mean value for that feature and species. The SVG rendering includes custom axis labels and styling from the included stylesheet.