Hi,
I had opted economicsas an optional subject. I would like to share my experiences regarding your query.
It is a common perception that economics paper in CSS is the same as one has learned in his or her graduation/ masters levels.
Actually economics is like any other optional subjets and it must be treated as such.
Questions that appear in paper usually contain multiple queries which need to be answered as you can see in the examples quoted by you.
What you have to ensure is that:
1. Your answers must answer all queries in the question
2. Every question should b answered by dividing the answer into headings and sub-headings.
3. Keep your answers as simple as possible; i.e. avoid complicated mathematical equations. However graphs and equations should be given where it is necessary.

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Zahid Morio