What term describes a government system that centralizes authority and does not tolerate opposition parties?

The term that describes a government system that centralizes authority and does not tolerate opposition parties is totalitarianism. In a totalitarian state, the government seeks to control all aspects of public and private life, often leading to the repression of political dissent and the elimination of any competing political parties. The central authority maintains strict control over the economy, media, education, and other institutions to ensure that their ideology prevails and to suppress any forms of opposition or criticism.

In contrast, democracy allows for the existence of multiple political parties and emphasizes freedoms such as free speech and the right to dissent. A republic is a form of democracy in which representatives are elected to make decisions on behalf of the citizens, while socialism refers to an economic system where the means of production are owned or regulated collectively, which can occur in both democratic and totalitarian contexts. Thus, totalitarianism is uniquely characterized by its centralized control and lack of tolerance for opposition, making it the correct answer in this context.