What are the most 2 common relays for running?

The two most common relay events in Track and Field are the 4x100 meter relay and the 4x400 meter relay. The 4x100 meter relay features four runners, each sprinting a 100-meter leg and passing a baton within a designated exchange zone. The 4x400 meter relay also has four runners, with each completing a 400-meter lap, emphasizing both speed and endurance. Both relays are highly strategic, focusing on smooth baton exchanges and team coordination.