This interactive tree chart visualizes a hierarchical classification of animals, branching from a central “Animal” node into mammals, reptiles, and birds, with leaf nodes for specific species. Each node is rendered as a circle whose size reflects a numeric value, while stroke and fill colors encode categorical attributes from the data. Built with D3 v5 and React, the visualization uses `d3.hierarchy` and `d3.tree` to compute node positions, draws curved links via SVG paths with `d3.select`, and styles circles and text labels directly in an SVG canvas.