This bar chart visualizes the average age of different cat breeds, sourced from a CSV dataset. Each breed is represented as a green bar, with the average age labeled above it. The chart is rendered as an SVG using D3.js v7 and dynamically sized based on the number of breeds. The code employs D3’s `d3.csv`, `d3.rollup`, and `d3.mean` to aggregate the data, then uses `d3.scaleBand` and `d3.scaleLinear` to position bars and axes. The visualization includes rotated x-axis labels, grid lines, and axis titles.