Why was russia divided between asia and europe?

in what part of asia did isis start?

The country of Turkey considers itself part of both Europe and Asia and uses the Bosphorus Straight as the dividing line, which puts the city of Istanbul and a small part of the country in Europe and a majority of Turkey's landmass in Asia. It's also important to note that in some parts of the world, Europe and Asia are considered a single continent, Eurasia. and all iknow about the other question is that isis started in southeast asia.