Final answer:
In a presidential system, the head of state serves a fixed term. An example of this is the President of the United States, who is elected to a four-year term. Countries such as Brazil and the Philippines also have a presidential system with fixed terms for their presidents.
Step-by-step explanation:
In a presidential system of government, the head of state serves a fixed term. This type of system distinguishes itself from others by having a separate executive branch, led by an elected president who is subject to term limitations. For example, the president of the United States is indirectly elected to a four-year term through the Electoral College and is typically term-limited. Other countries with presidential systems include Brazil and the Philippines, where presidents are directly elected and serve fixed terms. Variations exist, such as in Argentina, where the president can serve two four-year terms, take a four-year break, and then potentially be reelected for another two terms.
Contrastingly, in a parliamentary system, the political head of state, usually called a prime minister, is chosen by the majority party in the legislature and does not serve a fixed term. The presidential-parliamentary system combines elements of both, with a popularly elected president who may or may not have significant executive powers, alongside a parliament that selects a prime minister.
Therefore, when discussing governments where the head of state serves a fixed term, we refer primarily to the presidential system.