This example visualizes global health and wealth data as a bubble chart, where each circle represents a country positioned by life expectancy (y-axis) and GDP per capita (x-axis), with circle size encoding population and color encoding continent. It uses D3 v4’s scales (`scaleLinear`, `scaleLog`, `scaleSqrt`, `scaleOrdinal`) to map variables and renders SVG circles with axes labeled accordingly. The code loads CSV data via `d3.csv` and applies sorting by population, while styling uses opacity and a light grey background. The chart focuses on comparing country-level indicators, with axes labeled in French.