You often need to discuss a concept while answering a given question. Some concepts are so clear, concrete and well known that you just need to define and exemplify. Some concepts however are not very clear and obvious. In this case, in order to clarify them adequately , you need to define and elaborate them adequately.
In order to elaborate, you need to give suitable examples, analogies and often contrast them with other similar concepts. For instance, while dealing with the concept of sensory adaptation , you may define it as the process of diminishing sensation towards a constant environmental stimulus. This could even be more clear if we contrast the concept with the similar concept of habituation which is the process of diminishing attention towards a constant stimulus. Creating contrast is a good answering skill.
Here purpose is not to describe the second concept or give a comparative account of both concepts but to throw light on the main concept and make its semantic contours even more clear and distinct. This is a well known practice in creative as well as scientific writing. Make use of this skills and score better in the exams.
Arun kumar, Mentor – Beautiful Mind IAS