A simple yellow circle with eyes and an arc-based mouth forms a cartoon face in SVG. The eyebrows animate upward and back down using chained `transition()` calls with a 2-second duration each. The code builds the face with D3 v5 selections, positioning elements via `translate`, and constructs the mouth with the `arc()` helper, specifying inner and outer radii alongside start and end angles. The animation runs once on load within the fixed 960x500 viewport.