Answer:
The magma that melts in the upper mantle and erupts at the mid-ocean ridge has a different composition (higher in Ca, Mg, Fe and relatively lower in Si and Al) than the composition of the magma (more Si, Al, Na, K rich in relative terms) that built the continents. Melting different degrees (2%, 5%, 30%) of a rock with a mantle-like composition generates magma of different Al, Si contents. Continents grow at their edges by partial melting of oceanic crust that is being subducted, generating magmas of a somewhat more Si, Al-rich composition than the subducting slab itself. The chemistry and physics of melting a mixture of minerals rather than one homogeneous substance has the wonderful outcome of creating two distinct types of crust:
The creation of the wheel. Hope this helps!
Answer:
Nation-state describes Kosovo because almost all of the population belongs to a single ethnic group.
Explanation:
Kosovo is one of the most recent states to have formed in the world. It has separated from Serbia, and in practice, it functions as an independent country, but in theory, it is still not an independent country because it is not recognized by the United Nations, or rather by some of the most influential members of the United Nations. The demographics of Kosovo have changed a lot in the past 70 years.
The changes have mostly been toward a growing Albanian population, while the other ethnic groups were going down on the percentage of the total population. The reason for this has been that the Albanian population had the highest fertility rates, but also because of migration out of Kosovo by other ethnic groups because of safety reasons. This has resulted in a situation where Kosovo has become a nation-station, with over 92% of its population being comprised of ethnic Albanians (also referred to as Kosovars), while all other ethnic groups comprise less than 8% of the total population.
