They are all constitutional Monarchies!
A constitutional monarchy is a country that has a monarch, that is a queen or a king (such as Queen Elisabeth in the United Kingdom) but which at the same time has a constitution which is the supreme law of the land. In such countries typically the monarch only has a representative function.
It’s important to know how things worked before, so then if we know how they work, we could change it or leave it the way it is. Sometimes what worked back then doesn’t work now.
Senators are required to work on two standing committees during their term.
Well, to begin with, the Proclamation of 1763 was that any colonists were prohibited from establishing or maintaining settlements to the West of the Appalachian Mountains, only Native Americans could settle on that land. As a result the colonists were quickly angered arguing that they had the right to settle those lands. They had recently fought a war and they felt like they deserved it.