This example shows a scatter plot of the Iris dataset, mapping petal length to the x-axis and sepal length to the y-axis. The visualization renders circles as marks in an SVG, with scales defined using `scaleLinear` and axes created via `axisLeft` and `axisBottom`. Data is loaded asynchronously from a CSV URL using `d3.csv`, with numeric fields parsed through a custom row function. The chart fills the browser window, with margins applied to position the axes and plot area.