It is not true that despite some disagreements the United States is fundamentally a community of people with common interests. There is no one "national interest" represented in the Constitution, in the laws passed by Congress, in the decisions of the courts, in the development of capitalism, or in the culture of education and the mass media. The history of the US is not the history of a family, it's the history of a nation with strong conflicts of interest, between elite and non-elite, conquerors and conquered, masters and slaves, capitalists and workers, dominators and dominated in race and sex.
If you chose this observation, don’t just list how one group experienced bad conditions. Discuss how that showed different interests at work.
Because the elite in the nation is a small minority of the population, it must divide the mass of the population against itself (i.e., must keep various groups in society separated from each other) in order to prevent oppressed or marginalized people from uniting against them. Sexist, racist, nationalist/nativist, and other divisions in society reflect this need for division.
If you chose this observation, do not just list examples of sexist, racist, etc. policies. If you agree with the statement, you must make an argument about how these policies functioned to keep various groups in society divided against each other for the benefit of the elite. If you disagree, you must make an argument about why you think they did not.
There are three basic motivations for national action or policies in history: 1) Economics – the pursuit of economic gain, 2) Power - over other people in your nation or other nations, and 3) Ideology or benevolence – the idea that an action or a policy is actually best not just for your nation, but for other nations as well, or not just best for your own economic or social group, but also for other groups, or for your nation as a whole. Of all of these, in the United States, economics is the first in importance, power second, and ideology third, even if it claims otherwise.
If you chose this statement, and you agree with it, you need to make an argument that economic motivation is the most powerful motivation for national action by giving examples of times and places where the US chose economics or power over ideology in determining its actions or policies. This means you have to argue not only that economic considerations are present in an example, but how those considerations are PRIMARY above the other two considerations.
If you chose this statement, and you disagree with it, you then need to make an argument as to which order you think the three motivations should be in and again give examples which support that order – again, not just arguing that any particular motive is present in a situation, but why that motive is PRIMARY above the others.
Either way, you must make an argument about the relative importance of these motivations, not just list examples of each of them or say all three are important.
In history, and today, we need to understand, what do the winners tell the losers to keep them playing the game?
If you chose this statement, you need to make an argument regarding the idea that it's important to understand that "winners" always have a justification for why they "won" or why they are on top AND reasons why "losers" should accept the system as it is and just keep on trying to win within it. If you are confused about what this means, don't do this observation.