Answer:
the sequence of events in a story ... exposition. introduces the characters, setting, and basic situation ... In a story, the event that sets the main conflict into motion.
Since you didn't provide the excerpt, I am going to assume that the answer you need is 'hearken'.
Answer: Areas of defense in times of war
Explanation:
The except speaks of the potential of national unity in the United States being shattered as a result of a lack of a common enemy that the World Wars and Communism gave them.
The Fault lines in the excerpt refer to demarcations between opposing sides in the World Wars and in the Cold War that people then gathered behind to fight against their enemy. This made these lines become Areas of defense in essence that everyone came behind in solidarity to defeat their World War and Cold War enemies.
A single event in a story is called an incident. A plot is a series of incidents while a climax is the highest point in which resolution usually begins.
