Who primarily represents human cruelty in Buck's earlier experiences?

The man in the red sweater primarily represents human cruelty in Buck's earlier experiences. This character symbolizes the brutal treatment of Buck when he is taken from his comfortable life and thrust into a harsh and unforgiving environment. The man in the red sweater uses violence and intimidation to establish dominance over Buck, illustrating the harsh realities that many animals face at the hands of humans during the Gold Rush era. His cruel methods of breaking Buck's spirit not only highlight the brutality Buck endures but also serve as a pivotal moment in Buck's transformation from a domesticated pet into a creature that must fight for survival. This experience marks the beginning of Buck's journey into the wilderness where he learns the law of survival, and the man in the red sweater, with his cruelty, serves as a stark representation of the darker side of humanity that Buck must confront.