Read this excerpt from "rikki-tikki-tavi."nag coiled himself down, coil by coil, round the bulge at the bottom of the water-jar, and rikki-tikki stayed still as death. after an hour he began to move, muscle by muscle, toward the jar. nag was asleep, and rikki-tikki looked at his big back, wondering which would be the best place for a good hold. "if i don't break his back at the first jump,” said rikki, "he can still fight; and if he fights—oh, rikki! ” he looked at the thickness of the neck below the hood, but that was too much for him; and a bite near the tail would only make nag savage."it must be the head,” he said at last; 'the head above the hood; and when i am once there, i must not let go.”then he jumped. the head was lying a little clear of the water-jar, under the curve of it; and, as his teeth met, rikki braced his back against the bulge of the red earthenware to hold down the head. how does the protagonist move the plot forward in this excerpt?