Grassland are considered transitional biome BETWEEN THE FOREST AND THE DESERT BIOMES.
Grassland is described as transitional biome because it lies halfway between the forest and the desert biomes. Scientists believed that the areas that are forest today are grassland long time ago and those areas that are deserts are also believed to be grassland areas a long time ago. The areas where trees began to sprout in the grassland become a forest while the areas where grass died out become a desert. Because of this, the continents where both desert and forest biomes are found usually have a grassland lying in between them.