Final answer:
The line lengths and line breaks in Elegy most impact the poem's rhythm.
Step-by-step explanation:
The graphical element that most impacts the rhythm of the poem is the line lengths and line breaks in Elegy. The poet's use of line breaks creates pauses and breaks in the flow of the poem, which affects the pacing and rhythm. For example, in the poem, the line breaks and stanza breaks create pauses, indicating the shifting emotions and thoughts of the speaker. This adds to the overall rhythm of the poem and helps to convey the feelings of sadness and loss.