A written paper answer is marked by a person working through a stack of scripts under time pressure. The structure that scores is the one that makes your argument findable: a short introduction that states what you are going to argue, a body that develops it in clearly separated points, and a conclusion that answers the question that was actually asked.
Use headings or numbered points where the question invites them. A marker awarding points against a scheme can only credit what they can see - a correct idea buried mid-paragraph often earns nothing simply because it was never found.
Watch the command word. 'Discuss', 'evaluate', 'describe' and 'compare' each ask for something different, and writing everything you know about a topic in response to 'evaluate' will score below a shorter answer that actually weighs two sides.