Ihave an assignment, and i have to give three reasons of why battles happen in certain areas. any ideas?

1. Military and general advantages of either side fighting 
2. The sides are fighting over THAT area the battle takes place on to rule over or own
3. Any kind of dispute occurring either toward the territory or government near the turf

high entry costs prevent new producers from entering the market.

explanation:

an oligopoly is a term used to clarify the structure of a particular market, industry, or organization. a market is considered oligopolistic or amazingly focused when it is shared between a few companies.