This scatterplot visualizes the relationship between age and cholesterol levels across patients, with colors indicating gender: dark blue for males and pink for females. Using d3.scaleLinear, d3.extent, and SVG circles, the chart maps heart disease data points and includes an interactive legend. Hovering over the legend triggers a filter that dims the non-selected gender group, implemented through React state management and d3 event handlers. The visualization is rendered in a React application using D3 v7.