While race<span> and </span>ethnicity<span> share an ideology of common ancestry, they differ in several ways. First of all, </span>race<span> is primarily unitary. You can only have one </span>race<span>, while you can claim multiple </span>ethnic<span> affiliations. You can identify ethnically as Irish and Polish, but you have to be essentially either black or white.</span>
The fossil range can simply be defined as the time period in which an organism has existed, thus left fossil traces of its existence. The fossil range can be very short, medium, or long, thus usually there are limitations before certain type of organism evolves into another species, thus eliminating the ancestral organism from the fossil records. On the other hand, there are organisms that have incredibly big fossil ranges of several hundred million years, and since they emerged, they have remained almost unchanged. Those kind of fossil ranges are very rare though, and they don't represent the general picture. Most of the fossil ranges are between several thousand years and several million years, as that is usually how much a species exists, ending its reign, be it because of competition, changes in the environment, or big natural disaster.
The Seleucid Empire became a major center of Hellenistic culture it maintained the preeminence of Greek customs where a Greek political elite dominated, mostly in the urban areas. The Greek population of the cities who formed the dominant elite were reinforced by immigration from Greece.