Appositive phrases are used to further describe the nouns before them. They act like adjectives, although they aren't necessarily always adjectives. In most cases, they are separated from the rest of the sentence using commas on both sides. So yes, you are right - the appositive phrase in this sentence is either tulip or daffodil.
A Thesis Statement is what you need to start off your essay. Everything else in your essay must support the thesis statement so the answer is A
Abraham Lincoln adressed the American people with a speech that, as a side fact, is one of the most quoted speeches in the history of the U.S.
Over the years scholars have analyzed the speech, and they suggest that Lincoln used extreme care with his words. He wanted to deliver a heartfelt and precise message in moments of extreme national crisis. The magnitude of the battle in Gettysburg stunned the whole nation, and the dedication of a cementery at the site of the Civil War's most pivotal battle was seen as a solemn event, that empathized with the whole nation.
He placed this battle within the larger context of the American history, by making reference 87 years before to it's foundation. Lincoln sought to transform America by making an attempt at redefining liberty and nationalism by fusing the two together. Lincoln forever changed the way we think about the country.
Okay, as much as I love writing compare and contrast essays, I cannot write it for you. But, I can help you gather information and plan as well as revise your essay.