What part of the game indicates that an object has entered the battlefield as a copy of another object?

The correct answer is that it follows all copied abilities' triggers and actions. When an object enters the battlefield as a copy of another object, it does so by replicating all attributes of the original, which includes any abilities and characteristics that the original has. This means that any activated, triggered abilities, or static abilities are now associated with the new object, allowing it to interact with the game as if it were the original.

When a copy enters the battlefield, it does not just mimic the original's current state; it becomes that object fully, which means that it will also trigger any relevant abilities that would have activated based on its new identity. This is crucial in understanding how copied objects function within the context of Magic: The Gathering, as they need to resolve effects and triggers accordingly.

The other answer choices provide insufficient or misleading details regarding how copying works in the game. For instance, while the idea that it replaces everything about the original holds some truth, it doesn't emphasize the aspect of ongoing interactions associated with triggers and actions. Thus, understanding the copied abilities' triggers and actions is central to grasping the mechanics of copying in gameplay.