What transformation does Buck undergo throughout the story?

Buck's transformation throughout "The Call of the Wild" is profound and centered on his acceptance of his wild ancestry and instincts. Initially, Buck is a domesticated pet living a comfortable life. However, as he experiences the harsh realities of the wilderness and the brutal conditions of the Klondike, he begins to shed the layers of his domestication.

This journey is marked by his growing reliance on his instincts for survival, including hunting, fighting, and forming alliances with other dogs. As he is exposed to the challenges of the wild and the call of his ancestors, Buck becomes increasingly attuned to his primal nature. His return to the wild is not just a physical transformation but also an emotional and psychological one, culminating in his acceptance of his identity as a wolf.

In contrast, the other options do not accurately reflect Buck’s development throughout the story. He does not become more domesticated; in fact, he moves away from that lifestyle. While communication with humans is tested, it does not disappear completely. Lastly, Buck's surroundings profoundly affect him, and he is far from indifferent; he actively engages with his environment as he adapts to survive. Therefore, the correct interpretation of Buck's transformation is his acceptance of his wild instincts and ancestry.