Q. Which waterbody houses the "Kvarken" marine region?
Answer: Gulf of Bothnia
Notes: Kvarken marine region or the "throat of the sea" is a narrow marine region in the Gulf of Bothnia separating the Bothnian Bay from the Bothnian Sea. It is a marine region located between Sweden and Finland, in which on the Finnish side of Kvarken, there is a large archipelago, the Kvarken Archipelago, which includes large islands such as Replot, Bjorko, etc. This region was a historically important area also, as it was the main route of communication between Sweden and Finland during the Swedish rule.