This visualization displays the percentage composition of the Iris dataset, broken down by species and flower part measurements. The horizontal stacked bar chart uses d3.stack to aggregate the data, with each bar representing a different species and colored segments showing the proportional contribution of sepal length, sepal width, petal length, and petal width. The d3.scaleLinear and d3.scaleBand axes map the percentage values, while mouseover interactions trigger a tooltip that reports the exact percentage for each segment. The data is loaded from an external CSV file containing the classic Iris flower measurements.