What does Rinehart accomplish through the description of the lagoon in paragraphs 9-19?
She describes the lagoon to symbolize how prolonged exposure to death causes life to be treated as disposable.

She describes the lagoon to expand her observations from a narrow focus on trenches to a tactical assessment of the landscape.

She describes the lagoon to explain why the men are camped out in trenches and not pushing forward to a better location.

She describes the lagoon to strengthen her earlier observations about the barbarity of the men she interviews.