Question: What is the mountain range that separates Asia from the continent which has a greater history of unitary states?

full_context: Document 1: Geography of Russia: Truly alpine terrain appears in the southern mountain ranges. Between the Black and Caspian seas, the Caucasus Mountains rise to impressive heights, forming a boundary between Europe and Asia. One of the peaks, Mount Elbrus, is the highest point in Europe, at 5,642 meters. The geological structure of the Caucasus extends to the northwest as the Crimean and Carpathian Mountains and southeastward into Central Asia as the Tian Shan and Pamirs. The Caucasus Mountains create an imposing natural barrier between Russia and its neighbors to the southwest, Georgia and Azerbaijan.
Document 2: Federalism: China is the largest unitary state in the world by both population and land area. Although China has had long periods of central rule for centuries, it is often argued that the unitary structure of the Chinese government is far too unwieldy to effectively and equitably manage the country's affairs. On the other hand, Chinese nationalists are suspicious of decentralization as a form of secessionism and a backdoor for national disunity; still others argue that the degree of autonomy given to provincial-level officials in the People's Republic of China amounts to a de facto federalism.
Document 3: Federalism: Whilst it is often perceived as an optimal solution for states comprising different cultural or ethnic communities, the federalist model seems to work best in largely homogeneous states such as the United States, Germany or Australia, but there is also evidence to the contrary such as in Switzerland. Tensions between territories can still be found in federalist countries such as Canada and federation as a way to appease and quell military conflict has failed recently in places like Lybia or Iraq, while the formula is simultaneously proposed and dismissed in countries such as Ukraine or Syria. Federations such as Yugoslavia or Czechoslovakia collapsed as soon as it was possible to put the model to the test.
Document 4: Federalism: Federations often employ the paradox of being a union of states, while still being states (or having aspects of statehood) in themselves. For example, James Madison (author of the US Constitution) wrote in Federalist Paper No. 39 that the US Constitution "is in strictness neither a national nor a federal constitution; but a composition of both. In its foundation, it is federal, not national; in the sources from which the ordinary powers of the Government are drawn, it is partly federal, and partly national..." This stems from the fact that states in the US maintain all sovereignty that they do not yield to the federation by their own consent. This was reaffirmed by the Tenth Amendment to the United States Constitution, which reserves all powers and rights that are not delegated to the Federal Government as left to the States and to the people.
Document 5: Europe: This description is simplified. Sub-regions such as the Iberian Peninsula and the Italian Peninsula contain their own complex features, as does mainland Central Europe itself, where the relief contains many plateaus, river valleys and basins that complicate the general trend. Sub-regions like Iceland, Britain, and Ireland are special cases. The former is a land unto itself in the northern ocean which is counted as part of Europe, while the latter are upland areas that were once joined to the mainland until rising sea levels cut them off.
Document 6: Greece: Located in Southern Europe, Greece consists of a mountainous, peninsular mainland jutting out into the sea at the southern end of the Balkans, ending at the Peloponnese peninsula (separated from the mainland by the canal of the Isthmus of Corinth) and strategically located at the crossroads of Europe, Asia, and Africa. Due to its highly indented coastline and numerous islands, Greece has the 11th longest coastline in the world with 13,676 km (8,498 mi); its land boundary is 1,160 km (721 mi). The country lies approximately between latitudes 34° and 42° N, and longitudes 19° and 30° E, with the extreme points being:
Document 7: Federalism: In contrast, Europe has a greater history of unitary states than North America, thus European "federalism" argues for a weaker central government, relative to a unitary state. The modern American usage of the word is much closer to the European sense. As the power of the Federal government has increased, some people have perceived a much more unitary state than they believe the Founding Fathers intended. Most people politically advocating "federalism" in the United States argue in favor of limiting the powers of the federal government, especially the judiciary (see Federalist Society, New Federalism).
Document 8: Treaty: In function and effectiveness, the UN has been compared to the pre-Constitutional United States Federal government by some[citation needed], giving a comparison between modern treaty law and the historical Articles of Confederation.
Document 9: Geography of Europe: Europe is traditionally defined as one of seven continents. Physiographically, it is the northwestern peninsula of the larger landmass known as Eurasia (or the larger Afro - Eurasia); Asia occupies the eastern bulk of this continuous landmass and all share a common continental shelf. Europe's eastern frontier is delineated by the Ural Mountains in Russia. The southeast boundary with Asia is not universally defined, but the modern definition is generally the Ural River or, less commonly, the Emba River. The boundary continues to the Caspian Sea, the crest of the Caucasus Mountains (or, less commonly, the river Kura in the Caucasus), and on to the Black Sea. The Bosporus, the Sea of Marmara, and the Dardanelles conclude the Asian boundary. The Mediterranean Sea to the south separates Europe from Africa. The western boundary is the Atlantic Ocean. Iceland, though on the Mid-Atlantic Ridge and nearer to Greenland (North America) than mainland Europe, is generally included in Europe for cultural reasons and because it is over twice as close to mainland Europe than to mainland North America. There is ongoing debate on where the geographical centre of Europe falls.
Document 10: Iceland: Iceland is closer to continental Europe than to mainland North America, although it is closest to Greenland (290 km, 180 mi), an island of North America. Iceland is generally included in Europe for historical, political, cultural, geographical, and practical reasons. Geologically, the island includes parts of both continental plates. The closest bodies of land in Europe are the Faroe Islands (420 km, 260 mi); Jan Mayen Island (570 km, 350 mi); Shetland and the Outer Hebrides, both about 740 km (460 mi); and the Scottish mainland and Orkney, both about 750 km (470 mi). The nearest part of Continental Europe is mainland Norway, about 970 km (600 mi) away, while mainland North America is 2,070 km (1,290 mi) away, at the northern tip of Labrador.
Document 11: Federalism: Federalism in the United States is the evolving relationship between state governments and the federal government of the United States. American government has evolved from a system of dual federalism to one of associative federalism. In "Federalist No. 46," James Madison asserted that the states and national government "are in fact but different agents and trustees of the people, constituted with different powers." Alexander Hamilton, writing in "Federalist No. 28," suggested that both levels of government would exercise authority to the citizens' benefit: "If their [the peoples'] rights are invaded by either, they can make use of the other as the instrument of redress." (1)
Document 12: Asia: Asia is the largest continent on Earth. It covers 9% of the Earth's total surface area (or 30% of its land area), and has the largest coastline, at 62,800 kilometres (39,022 mi). Asia is generally defined as comprising the eastern four - fifths of Eurasia. It is located to the east of the Suez Canal and the Ural Mountains, and south of the Caucasus Mountains (or the Kuma -- Manych Depression) and the Caspian and Black Seas. It is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean and on the north by the Arctic Ocean. Asia is subdivided into 48 countries, three of them (Russia, Kazakhstan and Turkey) having part of their land in Europe.
Document 13: Asia: Asia is the largest continent on Earth. It covers 8.8% of the Earth's total surface area (or 30% of its land area), and has the largest coastline, at 62,800 kilometres (39,022 mi). Asia is generally defined as comprising the eastern four - fifths of Eurasia. It is located to the east of the Suez Canal and the Ural Mountains, and south of the Caucasus Mountains (or the Kuma -- Manych Depression) and the Caspian and Black Seas. It is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean and on the north by the Arctic Ocean. Asia is subdivided into 48 countries, three of them (Russia, Kazakhstan and Turkey) having part of their land in Europe.
Document 14: Politics of the United States: The United States is a federal republic in which the president, Congress, and federal courts share powers reserved to the national government according to its Constitution. At the same time, the federal government shares sovereignty with the state governments.
Document 15: Federalism: Until recently, in the absence of prior agreement on a clear and precise definition, the concept was thought to mean (as a shorthand) 'a division of sovereignty between two levels of government'. New research, however, argues that this cannot be correct, as dividing sovereignty - when this concept is properly understood in its core meaning of the final and absolute source of political authority in a political community - is not possible. The descent of the United States into Civil War in the mid-nineteenth century, over disputes about unallocated competences concerning slavery and ultimately the right of secession, showed this. One or other level of government could be sovereign to decide such matters, but not both simultaneously. Therefore, it is now suggested that federalism is more appropriately conceived as 'a division of the powers flowing from sovereignty between two levels of government'. What differentiates the concept from other multi-level political forms is the characteristic of equality of standing between the two levels of government established. This clarified definition opens the way to identifying two distinct federal forms, where before only one was known, based upon whether sovereignty resides in the whole (in one people) or in the parts (in many peoples): the federal state (or federation) and the federal union of states (or federal union), respectively. Leading examples of the federal state include the United States, Germany, Canada, Switzerland, Australia and India. The leading example of the federal union of states is the European Union.
ground_truth: the Ural Mountains
sub_queries: Who has a greater history of unitary states? Answer: Europe
the mountain range that separates Europe from asia is Answer: the Ural Mountains