This animated scatter plot visualizes the Iris dataset, cycling through different x-axis variables (petal width, sepal width, petal length, sepal length) while keeping sepal length on the y-axis. The SVG rendering uses D3's modular `scaleLinear`, `scaleOrdinal`, `axisLeft`, and `axisBottom` APIs to construct a reusable chart. Data points are colored and shaped by species, with a dynamic legend. The animation is driven by `setInterval`, re-calling the plot function to update axes and marks.