An interjection can also be named "an exclamation." It is a way to express oneself to display emotions. These words usually end with exclamation marks when they stand alone. If the word "Golly" was a so-called, "one word sentence," then it would end with an exclamation, particularly of surprise.
The function of your paper's conclusion is to restate the main argument. It reminds the reader of the strengths of your main argument(s) and reiterates the most important evidence supporting those argument(s).
