Final answer:
The Great Rift Valley separates the north central massif from the Plateau of Tigray in the Highlands of Ethiopia. This geological feature plays a critical role in the topography of the region.
Step-by-step explanation:
The north central massif is separated from the Plateau of Tigray by the Great Rift Valley.
The Ethiopian Plateau, containing the north central massif, and the Plateau of Tigray are part of the larger geographical feature known as the Highlands of Ethiopia. The Great Rift Valley, a significant geological formation in East Africa, divides the African Plate into the Somalian Plate and the Nubian Plate. This valley is discernible as the Western Rift and the Eastern Rift, with the Ethiopian Highlands situated to the northeast of the Eastern Rift Valley.
Lake Tana, located on the Ethiopian Plateau, is the source of the Blue Nile and exemplifies the complex hydrological characteristics of this highland region. The elevation of the north central massif and the Tigray region is notable, with Ras Dashan being the highest peak in the area, which amplifies the geographical distinction made by the Rift Valley.