What event leads to Buck's first major fight?

Buck's first major fight stems from a disagreement over food. This pivotal moment occurs when Buck, who is used to a life of relative ease, encounters the harsh realities of survival in the wild under human control. The crew, driven by the necessity of rations and the equivalent of a fighting instinct, leads to conflict as Buck struggles to assert his place in the hierarchy of the sled team.

The context of this event highlights Buck's transformation from a domesticated pet to a creature that must fight for survival. Food, a basic necessity, becomes a point of contention and demonstrates how the brutal conditions force Buck to adapt quickly. This fight is important as it marks the beginning of Buck’s journey into the wild, showcasing the instincts that begin to awaken within him as he faces challenges posed by both his fellow sled dogs and the harsh environment.

The other options, while reflective of significant themes in the story, do not align with Buck's first major conflict. Leadership challenges and fights with other teams occur later as Buck grows into his role, while attacking a wild animal is a different scenario that illustrates his evolution rather than his initial struggles. Thus, the disagreement over food serves as a foundational moment for Buck's character development and survival instinct.