The question appears to asking about what represents the poem's subject. First, we can imply what our general topic by the thesis. The thesis is usually the first sentence in a story, and is restated in the conclusion.
The first sentence is "I wandered lonely as a cloud." and the rest of the story details the poem's thesis.
This is clearly highlighting the cloud as the subject.
Brazil's independence differed from the rest of Latin America in that it was: declared and led by the Portuguese regent in Brazil, who became emperor. ... Leaders of Latin American independence revolts were generally: moderates, who wanted some democratic institutions but feared the masses.
