Final answer:
Mandelbaum identifies individual athleticism and teamwork and cooperation as features that make baseball a modern sport, emphasizing the structured nature of the game rather than rule absence or luck.
Step-by-step explanation:
According to Mandelbaum, the features that make baseball a modern sport include individual athleticism, teamwork and cooperation, and certainly not an absence of rules or a reliance on luck. The history of baseball shows its growth in popularity and the complex interplay of diverse cultural and social factors. The scandals and challenges faced, including the 1919 Chicago White Sox scandal, reflect how rules and integrity are integral to the sport's structure. Baseball's rise paralleled the development of modern sports characteristics such as professionalization, commercialization, and the creation of civic identities through team support.