This example demonstrates how to add an axis to a scatter plot using D3.js version 4. A dataset of coordinate pairs is plotted as circles, with each circle’s size scaled by its y-value using a square-root scale. The visualization renders in SVG and includes a bottom axis created with `d3.axisBottom()`, while linear scales (`d3.scaleLinear`) map the data domain to the visual range. Red text labels display each point’s coordinates next to the circles.