Essays are used to learn more about your reasons for applying to the course, university or company and your ability to benefit from and contribute to it. Your answers will let you state your case more fully than other sections of the application, and provide the evaluator with better insight about you and how you differ from the other applicants. In marginal cases, the essays are used to decide whether an applicant will be selected. The purpose of the admissions essay is to convey a sense of your unique character to the admissions committee. The essay also demonstrates your writing skills as well as your ability to organize your thoughts coherently. 
The function of an argumentative essay is to show that your assertion (opinion, theory, hypothesis) about some phenomenon or phenomena is correct or more truthful than others'. Argumentative writing is the act of forming reasons, making inductions, drawing conclusions, and applying them to the case in discussion; the operation of inferring propositions, not known or admitted as true, from facts or principles known, admitted, or proved to be true. It clearly explains the process of your reasoning from the known or assumed to the unknown. Without doing this you does not have an argument, you have only an assertion, an essay that is just your unsubstantiated opinion. 
Cause and Effect Essay
Cause and effect essays are concerned with why things happen (causes) and what happens as a result (effects). Cause and effect is a common method of organizing and discussing ideas.  The defining features of a "cause and effect" essay are causal chains that connect from a cause to an effect, careful language, and chronological or emphatic order. A writer using this rhetorical method must consider the subject, determine the purpose, consider the audience, think critically about different causes or consequences, consider a thesis statement, arrange the parts, consider the...