Which part of the government, according to the constitution, is made up of justices who make sure that laws are followed?

The correct answer is C. The Supreme Court. This court consists of Justices that are in that position for a lifetime. Their job is to reach a verdict on whether or not a law is constitutional and whether or not the people or states have been wronged by anything done by the government or the law itself. It's not much about the law as it is about the constitution.

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.