This bubble chart visualizes the relationship between average horsepower, torque, and highway MPG across 31 car makes. Each circle’s position encodes horsepower and torque on the x- and y-axes, while its radius scales with highway MPG, and its color distinguishes the make. The D3.js v7 example uses `d3.scaleLinear` for positioning and sizing, `d3.scaleOrdinal` with interpolated turbo colors for categorical encoding, and adds interactive tooltips on mouseover. A legend shows MPG values and a color key for all makes. Data comes from `bubblechart.csv`, rendered as SVG with hover animations.