`Not very stable
Monarchy
The most important form of leadership on Iran is the Islamic hierarchy that has the final say over government activities. The top religious ruler in Iran has the title of Ayatollah.
Iran had a monarchy before 1900. Qajar monarchy.
Mohammad Reza Shah Pahlavi was the Shah of Iran from 1941-79. He was deposed by the Islamic Revolution in 1979. After the Islamic Revolution, Iran changed its form of government to an Islamic Republic, and control was given to the leader of the Revolution: Ayatollah Khomeini. This new form of government is the form of government in present-day Iran, as well.
The current state of HTML is 5 at present. It is at it's most stable and advanced form.
Neither is actually a viable, stable form of government.
A government that rules a country form year to year without great change is usually a republic government. The power is usually with the people but only some of the people rule.
republic
a democracy .
Democracy
Afghanistan, Saudi Arabia, Iran, Pakistan etc
The Scottish government was formed in its current form in 1999. Prior to that, there was another government in place that was replaced by the current one.