A nation that is sovereign has a system of taxation. The countries that have sovereignity will have a system of taxation because they needed to support the country and must give the improvements of their country on their structures and services to their countrymen.
The correct answer is - has a system of taxation. Every nation that is sovereign has a system of taxation, they do differ from one country to another, but is something that is a must so that the country can function properly. The country is not obliged to be part of the United Nations, but is very useful if it is. It also doesn't mean that it has to obey another country, if that was the case, than there's no need or point of being sovereign. Most of the countries have outside influences, mainly from the world superpowers like USA, Russia, China, or regional powerful countries.
The original purpose of the Constitutional Convention of 1787 was to "A. revise the Articles of Confederation" since the Articles were far too "weak" for an effective government.
