Read these lines: "This first theft marked Buck as fit to survive in the hostile Northland environment. It marked his adaptability, his capacity to adjust himself to changing conditions, the lack of which would have meant swift and terrible death." What is the main point of the quoted lines?

1. 1. The theft is called a mark of fitness to survive, so the lines treat it as a sign rather than a crime. 2. 2. The sign is named directly: adaptability, the capacity to adjust to changing conditions. 3. 3. Without that capacity, the lines say, death would have followed swiftly. 4. 4. Nothing says the habit came from the south, and carelessness is the opposite of the fitness described. _Source: The Call of the Wild by Jack London (1903)_