This scatterplot visualizes the Iris dataset, plotting petal length against petal width. The visualization uses the D3.js library (v6.6.1) to fetch CSV data, map it to Cartesian coordinates with `scaleLinear`, and render circles as SVG marks. Axes are drawn using `axisLeft` and `axisBottom`, with the plot filling the browser window via `window.innerWidth` and `window.innerHeight`. The implementation highlights D3's modern `join` API for efficient SVG element updates.