The prime minister holds all the power while the president is a symbolic figure with little power. Iraq is an example of Dictatorship. This is when an individual or small group of individuals seize and hold power. No opposition is allowed. China is an example of a Communist country.
Communism is where the government own and run most of the businesses and farms.
The UK and USA are examples of Democracy. Democracy is government by the people using free elections to choose their representatives. In politics stupidity is not a handicap. If you succeed there are many rewards, if you disgrace yourself you can always write a book. Too bad all the people who know how to run the country are busy driving taxicabs and cutting hair.