A D3.js example demonstrates fundamental DOM manipulation by rendering a smiley face with movable eyebrows, using SVG elements. The code loads population data from a CSV file and appends rectangle shapes to the SVG canvas via `d3.select` and `d3.csv`, though the data is only logged to the console. The visualization relies on D3 v5’s selection and data-binding methods, with the face constructed through chained attribute calls on SVG elements.