When the colonists said "no taxation without representation," what did they mean?me asap

They basically meant that they wanted a say in what was taxed. This was mainly made because Britain taxed tea (most famous) and other necessities heavily, but they did not give the colonists any say in the matter, which was one of the snapping points of the tension between the two. (This also caused the Boston Tea Party) (oh and if you still have a question don't be afraid to ask) 

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.