The relation between writer and audience is a social relation, of which the relation between student writer and professorial audience is a particular instance. A few of these conventions are listed below. When in doubt about the requirements of your audience , ask. But there are several reasonable objections to this usage. For these and other reasons, many writers, teachers, and editors still reject the use of their and them to refer back to a singular antecedent.
Conservative prose has no connection with conservative politics.
Adopting conservative usage means hewing to those linguistic practices that bear professional writers' and editors' stamp of approval. Contractions in advice manuals convey a tone of comfortable common sense, and you'll notice that we've used them frequently in this Guide. But in a student essay contractions can give the impression that you're treating the subject casually rather than seriously. For this reason, they are best avoided. Coarse language and slang also suggest a casual rather than a serious approach to the subject, and they may convince your reader that you are too lazy to think of a more precise way to express dissatisfaction, disagreeableness, or disruption.