This scatter plot explores relationships between numeric columns of the auto-mpg dataset by letting users choose which variables appear on the x- and y-axes via two dropdown menus. The D3 v5 code uses the `scaleLinear` and `extent` functions to compute scales, `axisBottom` and `axisLeft` for styled grid lines, and a `transition().duration(2000)` to animate circles to their new positions when the axes change. Red semi-transparent circles represent each car, with axis labels updating to match the selected columns.