Why is the impact of starting the third paragraph with "but"?

Suppose you are a freshmen in college and you have not declared a major. one reason you enrolled at your respective college was the school's vibrant social life. at the same time, you want to balance your academic life because you know that your grades will matter for graduate school or job applications.you decide to forgo partying for two hours to study for an upcoming economics exam. in your first semester's principles of economics class, you learn that the enjoyment you would have received from partying is an example of a(n)

Any study/memorization tips? i have exams in a week and it would be great to try suggestions!you ; )

What is the one of the two issues involving slavery in the constitution