Question :
<span>The words adieu in line 36 entered our language do to
Answer :
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Only one firm selling all products in the market.
The absence of the substitutes of these suppliers.
The policy of unique product, i.e., absence of substitute the product sold by one firm,
Barriers to the entry and exit to the markets in terms of government, franchise, patents, copyrights, ownership.
Control of complete information e.g. secret formula.
The answer would be in contrast.