Answer: Weathering, erosion, and deposition from the terrestrial surface topography and soil characteristics. These processes, for example, have formed a variety of landforms in Texas like beaches, plateaus, mountains, and canyons as well as soil types like fertile soil, clay-rich soil, and sandy soil. The combination of topography, soil, and climatic conditions in an area defines the types of habitats that the area can support this is crucial to ecoregion classification. Ten separate ecoregions occur in Texas including 1) East Texas Pineywoods, 2) Gulf Coast Prairies and Marshes, 3) Oak Woods and Prairies, 4) Blackland Prairie, 5) cross timbers and prairies (6) Rolling Plains, (7) High Plains, (8) TransPecos, (9) South Texas Plains, (Brush Country), and (10) Edwards Plateau. Such ecoregions are named for the major types of habitats topographical features (e.g. Edwards Plateau) present in their areas. The weathering, erosion, and deposition of each of these ecoregions have an important influence. Hope This Helps :)