D3 Transitions demonstrates animated circle transitions using D3 version 7. The visualization renders six fixed-position circles that grow from radius zero to their target sizes over two seconds, with staggered delays, then rapidly move between hardcoded coordinates using a 500-millisecond linear ease. The code uses `select`, `transition`, and `easeLinear` from `d3`, applying data joins with explicit enter, update, and exit handlers. Enter animations expand circles, updates reposition them, and exits shrink them before removal, all within a light green SVG backdrop.