A bubble chart shows the correlation between three penguin measurements—bill length, bill depth, and body mass—across three species. Each circle is positioned by bill depth on the x-axis and bill length on the y-axis, with its size scaled by body mass via `d3.scaleLinear`. Colors encode species using `d3.scaleOrdinal`, and hover interactions trigger tooltip display via D3 event handlers. The chart is rendered as an SVG with axes, labels, and a legend, using data loaded from a CSV file.