The correct answer should be “it is not always stated overtly and is understood only by reading the whole poem”.
this is correct because the theme usually does not change itself, but there can be multiple themes analyzed. it is rarely stated overly and requires some analysis and understanding so as to find it.
They allow readers to multitask
One has to fall to build and grow the war. currents of water help the pine tree grow, so the pine is the war and the deaths are the currents