Grasslands: The climate here is too ? for most species of trees to survive. Some trees like aspen and willow are found in ?? valleys where more moisture is available. The deep, intertwined root systems of the grass forms a ??? which absorbs and stores ???. The grasslands consist of three sub regions. In the short grass prairie, ???-resistant short grasses, sagebrush, and cactus can survive. The long grass prairies is suitable for growing ??? and oil seeds. The parkland is a ??? zone of long grasses dotted with clumps of ??.
dry, river, sod mat, moisture, drought, sagebrush, cactus, grains, transition, trees.