Iris Scatter Plot
This scatter plot visualizes the Iris flower dataset, encoding four measurements (sepal and petal length/width) on the x- and y-axes. Users select the axes from dropdown menus, which re-renders the plot. The visualization distinguishes the three Iris species by color and includes a legend. Built with D3 v5, the example uses `scaleLinear`, `extent`, `axisBottom`, and `axisLeft` to construct the chart, and renders all elements as SVG, including the axes, axis labels, title, and data points.