Read the excerpt from The Call of the Wild.
The blood-longing became stronger than ever before. He was a killer, a thing that preyed, living on the things that lived, unaided, alone, by virtue of his own strength and prowess, surviving triumphantly in a hostile environment where only the strong survived. Because of all this he became possessed of a great pride in himself, which communicated itself like a contagion to his physical being. It advertised itself in all his movements, was apparent in the play of every muscle, spoke plainly as speech in the way he carried himself, and made his glorious furry coat if anything more glorious. But for the stray brown on his muzzle and above his eyes, and for the splash of white hair that ran midmost down his chest, he might well have been mistaken for a gigantic wolf, larger than the largest of the breed. From his St. Bernard father he had inherited size and weight, but it was his shepherd mother who had given shape to that size and weight. His muzzle was the long wolf muzzle, save that it was larger than the muzzle of any wolf; and his head, somewhat broader, was the wolf head on a massive scale.
Which theme does this passage illustrate?
Only the strong survive in the wilderness.
The desire to fight for power is an instinct.
The only way to learn something is to try it.
A good leader is strong and intelligent and treats his followers well.
answer:A