This interactive scatter plot visualizes the classic Iris dataset, allowing users to explore relationships between sepal and petal measurements across three flower species. Two dropdown menus let viewers select which measurement appears on the x- and y-axes. The visualization uses D3 v5's `scaleLinear`, `axisBottom`, and `axisLeft` to render axes and gridlines, while data points are drawn as SVG circles with color-coded species and an accompanying legend. When the axes change, the circles smoothly transition to their new positions using D3's `transition()`.