This interactive D3.js scatter plot visualizes the classic Iris dataset, displaying measurements of sepal length, sepal width, petal length, and petal width for three species of iris flowers. Users can dynamically select which measurement appears on the x-axis and y-axis via dropdown menus, with the plot updating accordingly. The visualization uses D3's `scaleLinear` for axes, `axisBottom` and `axisLeft` for rendering ticks, and `extent` to determine the domain of the selected data. Points are colored by species using an ordinal color scale, rendered as SVG circles.