天寒地冻的北极孕育出极具特色的生物圈。

Included in the diverse ecosystems of the Arctic are the Brooks mountain range in western North America, the enormous Greenland ice sheet, the isolated (孤立的) islands of the Svalbard archipelago (斯瓦尔巴群岛), the fjords (峡湾) of northern Scandinavia, and the grassland plateaus (高原) and rich river valleys of northern Siberia. They are home to some of the world’s toughest and most fascinating plants and animals.