Which two geographical regions are separated by high mountains?

The Palearctic and Oriental regions are indeed separated by high mountain ranges, specifically the Himalayas. This geographic distinction influences the distribution of flora and fauna, as the high altitudes create a barrier that impacts species migration and evolution. The Palearctic region covers parts of Europe, Asia, and North Africa, while the Oriental region includes the Indian subcontinent, Southeast Asia, and parts of southern China.

While the other regions listed have their own unique geographical features, they do not share such a significant barrier as high mountains that distinctly separates them. For instance, the Nearctic and Neotropical regions are divided mainly by the Tropic of Cancer and the Gulf of Mexico, and the Afrotropical and Australian regions are separated by the vast Indian Ocean, which does not involve high mountain ranges. The Oceanic and Continental distinction refers to different types of landmass but does not specifically relate to mountainous barriers. Therefore, the separation of the Palearctic and Oriental regions by high mountain ranges is the most accurate answer.