Russia's population density is 8.4 people per square kilometre (22 per square mile), making it one of the most sparsely populated countries in the world.
Speciation caused by gene flow is called SYMPATRIC SPECIATION.
Sympatric speciation is said to occur when speciation occurs in a population that live in the same geographical location. This type of speciation usually occur because of reduction in gene flow, that is caused by factors such as habitat differentiation, sexual selection and polyploidy.<span />
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Rocks break down as they interact with air and weather - Weathering
Density differences and other factors cause metals to concentrate in igneous rocks - volcanic activity
Seawater heats up from contact with hot rock, metals dissolves in it, the water rises and contacts cooler water, causing metals ores to settle on the ocean floor - hydro thermal energy
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