A reusable D3 scatter plot visualizes lung disease data, mapping age on the x-axis against lung capacity on the y-axis while coloring each point by smoking status. The chart is built as a customizable function, `scatterPlot()`, using D3 v6 scales (`scaleLinear`, `scaleOrdinal`) and axes to render the plot. A hover tooltip displays exact values for age, lung capacity, and smoking status. The rendering animates point appearance and uses `d3.schemeCategory10` for color assignment, with data bound directly to circles.