Final answer:
International swimming races are measured in meters, with standard pool race distances like 50, 100, or 200 meters, and kilometers for open water swimming.
Step-by-step explanation:
The distance in international swimming races is measured using meters, adhering to worldwide standards that specify lengths in this unit. This ensures that a race covering 100 meters in one country is exactly the same distance as a 100-meter race in another, providing a universal basis for comparison. Just as surveyors measure land distance and astronomers measure cosmic distances with a standard unit, the distances in swimming competitions are precisely defined. In Olympic-sized pools, races often occur over distances of 50 meters, 100 meters, 200 meters, and so on, with longer races measured in kilometers for open water swimming.