Compare and contrast pure competition and oligopolistic competition

What will be an ideal response?

Under pure competition, the market consists of many buyers and sellers trading in a uniform commodity, such as wheat, copper, or financial securities. No single buyer or seller has much effect on the going market price. In a purely competitive market, marketing research, product development, pricing, advertising, and sales promotion play little or no role. Thus, sellers in these markets do not spend much time on marketing strategy.
On the other hand, under oligopolistic competition, the market consists of only a few large sellers. Because there are few sellers, each seller is alert and responsive to competitors' pricing strategies and marketing moves.