Is it true that some people just need to experience the negative impacts of their decisions despite being shown the consequences by those who have already experienced them? what are the reasons?

How did the end of the mexican american war result in growing sectionalism in the united states?

Which of the principles do you feel is more important for our our american society? respond in 3 sentences. (principals: popular sovereignty, republicanism, federalism, separation of powers, checks and balances, limited government, or individual rights)

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.