What is difference between a monarchy and a republic?

Explanation:

if you mean constitutional monarchy, then as both are representative democracies, the difference is elected versus hereditary heads of state. In a republic the head of state is elected somehow, whether that be popularly or through some other mechanism such as the legislature or an electoral college.

What is the difference between a republic and a democracy?

The major difference between a democracy and a republic is that a republic is a form of government whereas a democracy is an ideology that helps shape how a government is run. Put another way: a republic is the system of government that allows a country to be democratic

the noble might have thought that the system was far because they had lot of things and riches and the serf would have thought that the feudal system was un fair because of the way they were treated.

newly independent countries of the former ussr