This example visualizes the relationship between flipper length and body mass across three penguin species from a CSV dataset. D3.js v7 loads the data with `csv` and renders an SVG scatter plot, coloring each point by species using a custom marker function. The x-axis maps flipper length, the y-axis maps body mass, while radius and color are also encoded with culmen dimensions and species. Axes are generated with `axisLeft` and `axisBottom`, paired with scaleLinear and extent domains.