What is the theme of the book called "call of the wild" by jack london?

The Indispensable Struggle for Mastery. The Call of the Wild is a story of transformation in which the old Buck—the civilized, moral Buck—must adjust to the harsher realities of life in the frosty North, where survival is the only imperative.

post the passage. we don’t know what you’re talking about

its everything except for telling nonfiction and using first person