Why aren't mountain ranges or polar ice caps classified as biomes?

Mountain ranges and polar ice caps are not classified as biomes because they do not meet the criteria for a biome, which is a large geographic area with distinct climate, plants, and animals. Mountain ranges and polar ice caps have extreme conditions and limited biodiversity compared to traditional biomes like forests or grasslands. Additionally, they are often considered as part of other biomes, such as tundra or alpine biomes.