Answer:
Topics with a limited, or specific, scope are easier to explain carefully and in detail than topics that are vague, amorphous, or very broad. For example, general subjects such as mountains, automobiles, or music sound systems are so broad that it's hard to know where to begin. However, a specific aspect of sound systems, such as compact discs (CDs) is easier. Within the subject of CDs, of course, there are several topics as well (design, manufacturing process, cost, marketing, sound quality, comparison to tape and vinyl recordings, etc.).