This interactive bubble chart visualizes correlations among penguin measurements—body mass, bill length, and flipper length—using the Palmer Penguins dataset. Each circle’s x-position maps bill length, y-position maps body mass, and radius encodes flipper length. Colors distinguish species, with a legend for flipper size. Hovering reveals the species via a tooltip. Built with D3 v7, the chart uses SVG, linear scales, a color ordinal scale, and event handlers for interactivity.