order the topics from broadest to narrowest.\nbroader\nseabiscuits win at pimlico race course in 1938\nthe…

Brief Explanations:

The topic "famous racehorses of the twentieth century" is the broadest as it encompasses a large group (all famous racehorses in a century). "The life of the famous racehorse Seabiscuit" is narrower as it focuses on one specific racehorse (Seabiscuit) but still covers his whole life. "Seabiscuit's win at Pimlico Race Course in 1938" is the narrowest as it is a single event in the life of one racehorse.

Answer:

famous racehorses of the twentieth century, the life of the famous racehorse Seabiscuit, Seabiscuit's win at Pimlico Race Course in 1938