Answer:
Market control by a few large firms
Difficult entry
Mutual interdependence
Step-by-step explanation:
In the case of oligopoly as we know that there are very little large firms and each kind of firm generates the important portion of the total output. So each market have the market control
Also the main reason behind the barrier with regard to new firm entered is the barrier for the few firms. The reasons like patents, large capital needed are some reasons that makes it difficult for entering
In addition to this, they are mutual interdependent. This implies that the one firm action would impact the other firm action and according to this, the price and the level of output would be determined
Hence, the above represent the answer