A “republic” is a form of government that is not a monarchy and functions by a method of public assembly. The word “democratic” describes a form of ruling a government by all the people or all the population as opposed to a select group in oligarchy or one person rule in autocracy. Democratic means a government that operates by democracy. Democratic entities exist across a spectrum of criteria and is not a binary feature. There is no one criteria that makes or breaks a democracy. A government with 20 democratic features is “more” democratic than another with only 19 democratic features. The word “federal” describes a form of administration that is in contrast to another form called “unitary”. A federal government administers a nation by granting limited autonomy to sub-national administrative units. The regional units have defined but limited powers to exercise independent of the central government. The contrasting form of a unitary government has an hierarchical organization like a military chain of command. A federal system applies the concepts of federalism that are usually more expensive and more complex than the unitary system. A federal system is wise to use in countries with high diversity due to languages and ethnicities. A federal system is obstructive to tyrannical efforts and obstructive to democratic aspirations. Hope this helped!
It can be defined as a federation of states with a central government in republican form. In this type of government the central government has no authority to take back the authorities of a state government.
When a good has a more expensive substitute (either because it is of better quality or gives you more status) and it's demand increases when the income improves we can figure out which the inferior goods are. The inferior goods are the ones that are replaced when this occur. So the demand drops when the income improves.