What physical feature is common in both the Great Plains and the Coastal Plains regions of Texas?

The Rio Grande Plain shows characteristics of both the Gulf Coastal Plains and the North Mexico Plains because there is similarity of topography, climate, and plant life all the way from the Balcones Escarpment in Texas to the Sierra Madre Oriental in Mexico, which runs past Monterrey about 160 miles south of Laredo.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).