How to make case-study on Sales and Marketing division of an enterprise?

To understand the Sales and Marketing division and before a figure out the problematic area, need to  answer following question
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Who?
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Who is responsible for Marketing decision?
Who is responsible for Sale?
Who is responsible for Customer Care?

Establish relation
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What are the links between marketing, sales and CC?

Do they conceive of marketing as a broader way to position their firms? answer following question:-

For example head of both departments are same or not?
                    if same what is major? (gm, met, sales, director)
                    is any agency or team taking care of any dept?
                    Conflict area?

Find Cultural difference
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How each team operate?
How are they Influencing corporate decision?

Find Economic differences
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what is the budget for each department or team?
what is opinion of sales on product price, promotion price, value proposition?