This stacked bar chart visualizes the percentage distribution of the four Iris flower measurements (sepal length, sepal width, petal length, and petal width) for each of the three Iris species. The data comes from the classic Iris dataset, which is loaded and transformed using D3's `d3.stack()` and `d3.scaleOrdinal()` for color encoding. The visualization uses `d3.axisBottom` and `d3.axisLeft` for its scales, with interactive tooltips appearing on mouseover events. The SVG rendering approach arranges the stacked segments horizontally across each species band, with the x-axis representing percentage values.