What does the young recruits ("the infants") symbolize in the book? support with references

Certainly they represent innocence. As the war drags on they get younger and younger. They are essentially virgins with rifles fighting in hell when they should really be playing in school. At one point Paul describes the terror these "infants" go through,

"Beside us lies a fair-headed recruit in utter terror. He has buried his face in his hands, his helmet has fallen off. I fish hold of it and try to put it back on his head. He looks up, pushes the helmet off and like a child creeps under my arm, his head close to my breast. The little shoulders heave."