Answer:
1) The track is 200 meters long, the athletes do 4 rounds, so the total distance ran is:
4*200 meters = 800 meters
2) The displacement is defined as the difference between the final position and the initial position.
When you are in a track, and you run a full round, you end in the same position where you started, so the total displacement is 0 meters.
3) As they are running in a closed track (for example, a circular track), they must change the direction of motion at some point, so the motion is not uniform (uniform motion happens when the movement is always in the same direction and always at the same speed)
4) no, is not equal because in the end, the total distance is 800 meters and the displacement is 0 meters.