What is the purpose of an introduction in an essay

Which techniques best describe the tone the author is using in this passage?

Read the excerpt from martin luther king jr.’s "i have a dream” speech. and so let freedom ring from the prodigious hilltops of new hampshire. let freedom ring from the mighty mountains of new york. let freedom ring from the heightening alleghenies of pennsylvania. let freedom ring from the snow-capped rockies of colorado. let freedom ring from the curvaceous slopes of california. but not only that: let freedom ring from stone mountain of georgia. let freedom ring from lookout mountain of tennessee. let freedom ring from every hill and molehill of mississippi. from every mountainside, let freedom ring. the most likely reason king uses allusions in this part of his speech is to share his knowledge of american geography. compare northern and southern destinations. remind listeners about small-town accountability. encourage listeners to envision freedom everywhere.

Go, wondrous creature! mount where science guides, go, measure earth, weigh air, and state the tides; instruct the planets in what orbs to run, correct old time, and regulate the sun; which statement is correct? antithesis is used in the first two lines. antithesis is used in the last two lines. parallelism is used in the first two lines. parallelism is used in the last two lines.