Final answer:
Jack London's depiction of Buck's metamorphosis in 'The Call of the Wild' symbolizes the transformation from a domesticated pet to a wild, dominant lead sled dog.
Step-by-step explanation:
When London speaks of Buck metamorphosing, he means that Buck changed into a different kind of dog. In Jack London's novel The Call of the Wild, Buck is a domesticated dog who is forced into the harsh environment of the Klondike Gold Rush as a sled dog. Throughout the story, Buck undergoes a transformation as he adapts to the brutal conditions, reverting to his primal instincts to survive and ultimately dominating the sled dog team. This metamorphosis signifies the profound change in Buck from a pampered pet to a creature in tune with his natural, ancestral roots.