This example visualizes the Iris dataset as a scatter plot, mapping petal length and width on the x and y axes while coloring each point by species (setosa, versicolor, or virginica). The code loads CSV data via `d3.csv`, parses numeric fields, and uses `d3.scaleLinear` with `d3.extent` to compute domains. Circles are rendered as SVG elements with `d3.selectAll` and `data().join()`, while axes are added using `d3.axisLeft` and `d3.axisBottom`. Axis labels are drawn with SVG `text` elements.