A donut plot displays stacked bar charts of health condition counts—hypertension, diabetes, asthma, and HIV—across racial groups using data from health_indicators_2019.csv. The D3.js code stacks the categorical data with the `stack` function and renders rects with `scaleLinear` and `scaleBand` axes. Interactive tooltips appear on mouseover, showing the condition name and count, positioned via D3's `mouse` function. The visualization uses an SVG canvas from the index.html file.