How do the following market structures affect pricing, distribution and product and service offering affect 1-monopolistic competition...

Under monopolistic competition, there are a large number of companies in the market, but the products each one sells are a little bit different. They aren't completely different---they are substitutes---but they are also not exactly interchangeable---they are not perfect substitutes.

Restaurants are a good example; any restaurant will serve you food, and if one restaurant gets too expensive you can change to another; but some restaurants are better than others, and you'll be disappointed if your favorite restaurant gets too expensive and you have to switch.

Monopolistic competition results in higher prices, higher profits, and lower quantity sold than would occur under perfect competition, but lower prices, lower profits, and higher quantity sold than would occur under monopoly. If companies can join the market, they can also make a monopolistic competition more competitive over time, eventually driving it toward perfect competition in the long run.

Under monopsony, there are many companies selling the good, but there is only one entity buying it. As a result, the buyer has the power to set prices.

Government contracts are an example of monopsony. If you want to build F-16s, the only place you're allowed to sell them to is the US military. As a result, the US military gets to set the price at which they will buy those F-16s.

Monopsony results in lower prices and lower profits than even perfect competition; it also results in lower quantity sold, which can be a bit counter-intuitive since both monopoly and monopsony result in reduced quantity sold even though one raises prices and one lowers them.

Finally, there is duopoly, in which there are only two companies selling the good. A complex game emerges, in which each company must strategize about what their competitor will do in order to set their next move.

Commercial airliners are an example of duopoly; Boeing and Airbus together control almost the entire market.

Many different outcomes are possible under duopoly.

If the two companies can manage to collude, they will coordinate their prices and essentially act as two shareholders of the same monopoly. This is usually illegal if you do it outright; but there are ways of being more subtle. One way is to make a subtle but credible threat that if they lower their prices, so will you, and as a result of the price war you will both lose out. If the threat is credible enough, both companies will keep offering the high price and act as a monopoly.

Alternatively, the threat could be completely non-credible and the two companies could compete as fiercely as possible, driving the price down to the same as it would be under perfect competition. This is called Bertrand competition.

There is also a third possibility, which might occur for example if the companies are competitive, but work in capital-intensive industries where it is costly to change the quantity you produce in a short time. An intermediate state can emerge, where each company basically takes the other company's level of production as fixed and then sets their own to monopolize their share of the market. The result is a state called Cournot competition, and, similar to monopolistic competition, its effects are intermediate between monopoly and perfect competition.