Final answer:
In Chapter 13 of 'A Separate Peace,' the trucks are filled with young men heading off to WWII, symbolizing the transition from the peaceful life at Devon School to the harsh realities of war.
Step-by-step explanation:
In Chapter 13 of A Separate Peace, the trucks are carrying young men who are being taken to participate in World War II after they have enlisted. The protagonist, Gene, notices the soldiers in the back of the trucks and reflects on the reality and the inevitability of his and his friends' participation in the war. The scene is symbolic of the loss of innocence and the transition from the sheltered life of Devon School to the harsh realities of the adult world and wartime.
The trucks highlight the overarching theme of war in the novel, serving as a constant reminder to the students and readers that the peace experienced at Devon will soon be disrupted by the impact of the war. This chapter strikes a chord with the grim transformation the main characters are about to undergo as they face the future.