This area chart visualizes the relationship between age and weight using a steel blue filled region beneath a line path. The visualization loads CSV data from an external GitHub URL and renders it as an SVG, with age plotted on the x-axis and weight on the y-axis. The code uses d3.csvParse to process the data, d3.scaleLinear for both axes, and d3.area to generate the chart’s filled shape. Axis labels and a chart title clarify the variables, while the data is sorted by age before rendering to ensure a coherent curve.