Read the excerpt from "Pilgrimage.”

Here, the Mississippi carved
its mud-dark path, a graveyard

For skeletons of sunken riverboat.
Here, the river changed its course,
Turning away from the city
as one turns, forgetting, from the past—

The abandoned bluffs, land sloping up
above the river’s bend—where now

The Yazoo fills the Mississippi’s empty bed.

Pilgrimage, "Elegy for the Native Guards", "South" from Native Guard by Natasha Trethewey. Copyright (c) 2006 by Natasha Trethewey. Used by permission of HarperCollins Publishers.

Which universal theme is shown in the excerpt?

the wisdom gained from experience
the impact of the past on the present
the value of learning
the sufferings of war