Answer and explanation:
At the end of the novel "The Call of the Wild" by Jack London, the characters are separated because John Thornton dies and Buck is finally free to heed the call of the wild.
Buck is a dog that gets stolen from his comfortable home in California to be sold as a sled-dog. John Thornton, at some point in the story, becomes his owner. Buck shows great love and loyalty for John, and serves him even though he (Buck) has already felt that his place is in the wilderness, with the wolves.
When John dies, Buck mourns him, but finally accepts the call he has been feeling and goes to live in the forest with the wolves. The novel is based on the "survival of the fittest" idea. It is one of Jack London's most famous works.
