Read the excerpt from “Comprehending the Calamity.” The shock came, and hurled my bed against an opposite wall. I sprang up, and, holding firmly to the foot-board managed to keep on my feet to the door. The shock was constantly growing heavier; rumbles, crackling noises, and falling objects already commenced the din.

The door refused to open. The earthquake had wedged it in the door-frame. My husband was pushing on the opposite side and I pulled with all my strength, when a twist of the building released it, and the door sprang open.

We braced ourselves in the doorway, clinging to the casing. Our son appeared across the reception room, and my husband motioned to him to stand in his door also, for fear of the chimney.

Which best describes the organizational structure of this passage?