Read this excerpt from The Call of the Wild.

A hundred yards ahead the path turned and sloped steeply into the main street. It would have required an experienced man to keep the top-heavy sled upright, and Hal was not such a man. As they swung on the turn the sled went over, spilling half its load through the loose lashings. The dogs never stopped. . . . They were angry because of the ill treatment they had received and the unjust load. Buck was raging. He broke into a run, the team following his lead.

What do readers learn in this excerpt that they might not know if Hal narrated the story?

the role that the shape of the path plays in the sled turning over
the real reason why the dogs continue to run after the sled turns over
the difficulty that a driver has in keeping a sled upright on sharp turns
the role that the loose lashings play in the sled losing its load