This chart shows how weight changes with age as a filled area, with age on the x-axis and weight in kilograms on the y-axis. The data is loaded from a remote CSV file and parsed with `d3.csvParse`. The visualization uses D3 v7 to create an SVG with a linear scale for both axes. An area path is generated with `d3.area` and appended to a group element, with green fill. Axis labels and a title are added using `d3.axisBottom` and `d3.axisLeft`.