This bubble chart visualizes the correlation between GDP per capita, life expectancy, and population area ratio across 20 countries. Each circle’s position encodes GDP per capita on the x-axis and life expectancy on the y-axis, while its size reflects population density. The code uses d3.csv to load data, d3.scaleLinear for axes and bubble sizing, and d3.scaleOrdinal with schemeCategory10 for country colors. Interactive tooltips appear on mouseover, and a legend is built with SVG circles and text labels.