Complex sentence: Algeria, Egypt, Libya, Morocco, Tunisia, Western Sahara (claimed by Morocco), Sudan and South Sudan, they form the UN subregion of Northern Africa which also makes up the largest bloc of the Arab World.
Split into simpler sentences: Algeria, Egypt, Libya, Morocco, Tunisia, and Western Sahara (claimed by Morocco). Together with the Sudan and South Sudan, they form the UN subregion of Northern Africa which also makes up the largest bloc of the Arab World.