These children have often been kept in such extraordinary terrifying and confusing circumstances that I am more amazed that they survive psychologically at all than I am that they manage to preserve themselves by a desperate redrawing of their boundaries. What they do, when confronted with overwhelming conflict and pain, is this: They "leave." They create a boundary so that the horror doesn't happen to them; it either happens to no one, or to some other self, better able to sustain its organization under such an onslaught--at least that's what they say they did, as best they recall.
The essay, which follows is an opinion piece that was written for The Globe and Mail. The style is therefore journalistic but aimed at a fairly sophisticated readership. Paragraphs are short, as is normal in a newspaper with its narrow columns, and the tone is more conversational than would be appropriate for a formal essay. Notice the clear statement of the thesis, the concrete illustrations in the body of the essay, and the way the conclusion leads to a more general statement of what is perhaps to come in the future. It is included here both because it is a good example of the essay form and because it explores the kind of problem you will come up against as you try to punctuate your essays correctly.
Longer essays may also contain an introductory page that defines words and phrases of the essay's topic. Most academic institutions require that all substantial facts, quotations, and other porting material in an essay be referenced in a bibliography or works cited page at the end of the text. This scholarly convention helps others (whether teachers or fellow scholars) to understand the basis of facts and quotations the author uses to support the essay's argument and helps readers evaluate to what extent the argument is supported by evidence, and to evaluate the quality of that evidence. The academic essay tests the student's ability to present their thoughts in an organized way and is designed to test their intellectual capabilities.