Read the excerpt from The Call of the Wild. The Yeehats were dancing about the wreckage of the spruce-bough lodge when they heard a fearful roaring and saw rushing upon them an animal the like of which they had never seen before. It was Buck, a live hurricane of fury, hurling himself upon them in a frenzy to destroy. He sprang at the foremost man (it was the chief of the Yeehats). . . . He did not pause to worry the victim, but ripped in passing, with the next bound tearing wide the throat of a second man. There was no withstanding him. He plunged about in their very midst, tearing, rending, destroying, in constant and terrific motion which defied the arrows they discharged at him. In fact, so inconceivably rapid were his movements, and so closely were the Indians tangled together, that they shot one another with the arrows; and one young hunter, hurling a spear at Buck in mid air, drove it through the chest of another hunter with such force that the point broke through the skin of the back and stood out beyond. Then a panic seized the Yeehats, and they fled in terror to the woods, proclaiming as they fled the advent of the Evil Spirit.

Which theme does this passage illustrate?

The only way to learn something is to try it.
Only the strong survive in the wilderness.
A good leader is strong and intelligent and treats his followers well.
The desire to fight for power is an instinct.